21431643156 has 144 divisors (see below), whose sum is σ = 70478972928. Its totient is φ = 5324616000.

The previous prime is 21431643139. The next prime is 21431643173. The reversal of 21431643156 is 65134613412.

21431643156 is a `hidden beast` number, since 2 + 1 + 4 + 3 + 1 + 643 + 1 + 5 + 6 = 666.

It is an interprime number because it is at equal distance from previous prime (21431643139) and next prime (21431643173).

It is a super-2 number, since 2×21431643156² (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 21431643156.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 104320 + ... + 231831.

It is an arithmetic number, because the mean of its divisors is an integer number (489437312).

Almost surely, 2^21431643156 is an apocalyptic number.

It is an amenable number.

21431643156 is an abundant number, since it is smaller than the sum of its proper divisors (49047329772).

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

21431643156 is a wasteful number, since it uses less digits than its factorization.

21431643156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 336202 (or 336197 counting only the distinct ones).

The product of its digits is 51840, while the sum is 36.

The spelling of 21431643156 in words is "twenty-one billion, four hundred thirty-one million, six hundred forty-three thousand, one hundred fifty-six".