1221126164640 has 288 divisors, whose sum is σ = 4226875773120. Its totient is φ = 320967733248.

The previous prime is 1221126164581. The next prime is 1221126164669. The reversal of 1221126164640 is 464616211221.

1221126164640 is a `hidden beast` number, since 1 + 2 + 2 + 1 + 1 + 2 + 6 + 1 + 6 + 4 + 640 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

It is a super-2 number, since 2×1221126164640² (a number of 25 digits) contains 22 as substring.

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 = 1221126164595 and 1221126164604.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 235781571 + ... + 235786749.

It is an arithmetic number, because the mean of its divisors is an integer number (14676651990).

Almost surely, 2^{1221126164640} is an apocalyptic number.

1221126164640 is a gapful number since it is divisible by the number (10) 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 1221126164640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2113437886560).

1221126164640 is an abundant number, since it is smaller than the sum of its proper divisors (3005749608480).

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

1221126164640 is a wasteful number, since it uses less digits than its factorization.

1221126164640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7516 (or 7505 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The spelling of 1221126164640 in words is "one trillion, two hundred twenty-one billion, one hundred twenty-six million, one hundred sixty-four thousand, six hundred forty".