1217052121428 has 576 divisors, whose sum is σ = 3971565561600. Its totient is φ = 308558315520.

The previous prime is 1217052121427. The next prime is 1217052121433. The reversal of 1217052121428 is 8241212507121.

1217052121428 is a `hidden beast` number, since 1 + 2 + 1 + 70 + 521 + 21 + 42 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 1217052121392 and 1217052121401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1217052121427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 320528026 + ... + 320531822.

It is an arithmetic number, because the mean of its divisors is an integer number (6895079100).

Almost surely, 2^{1217052121428} is an apocalyptic number.

1217052121428 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1217052121428, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1985782780800).

1217052121428 is an abundant number, since it is smaller than the sum of its proper divisors (2754513440172).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1217052121428 is a wasteful number, since it uses less digits than its factorization.

1217052121428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3992 (or 3987 counting only the distinct ones).

The product of its (nonzero) digits is 17920, while the sum is 36.

Adding to 1217052121428 its reverse (8241212507121), we get a palindrome (9458264628549).

The spelling of 1217052121428 in words is "one trillion, two hundred seventeen billion, fifty-two million, one hundred twenty-one thousand, four hundred twenty-eight".