20661207156 has 36 divisors (see below), whose sum is σ = 52233103104. Its totient is φ = 6886256400.

The previous prime is 20661207103. The next prime is 20661207163. The reversal of 20661207156 is 65170216602.

It is a happy number.

20661207156 is a `hidden beast` number, since 20 + 6 + 612 + 0 + 7 + 15 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-2 number, since 2×20661207156² (a number of 21 digits) contains 22 as substring.

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

It is a self number, because there is not a number n which added to its sum of digits gives 20661207156.

It is a congruent number.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 328621 + ... + 386411.

Almost surely, 2^20661207156 is an apocalyptic number.

It is an amenable number.

20661207156 is an abundant number, since it is smaller than the sum of its proper divisors (31571895948).

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

20661207156 is a wasteful number, since it uses less digits than its factorization.

20661207156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67732 (or 67727 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 36.

The spelling of 20661207156 in words is "twenty billion, six hundred sixty-one million, two hundred seven thousand, one hundred fifty-six".