1221620022 has 128 divisors (see below), whose sum is σ = 3256934400. Its totient is φ = 331851168.

The previous prime is 1221620011. The next prime is 1221620027. The reversal of 1221620022 is 2200261221.

1221620022 is a `hidden beast` number, since 1 + 2 + 21 + 620 + 0 + 22 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 1221619977 and 1221620004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221620027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1973229 + ... + 1973847.

It is an arithmetic number, because the mean of its divisors is an integer number (25444800).

Almost surely, 2^1221620022 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221620022, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1628467200).

1221620022 is an abundant number, since it is smaller than the sum of its proper divisors (2035314378).

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

1221620022 is a wasteful number, since it uses less digits than its factorization.

1221620022 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 887 (or 881 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 1221620022 is about 34951.6812471160. The cubic root of 1221620022 is about 1069.0024831615.

Adding to 1221620022 its reverse (2200261221), we get a palindrome (3421881243).

The spelling of 1221620022 in words is "one billion, two hundred twenty-one million, six hundred twenty thousand, twenty-two".