21655043231156 has 12 divisors (see below), whose sum is σ = 37941494105760. Its totient is φ = 10814616343800.

The previous prime is 21655043231137. The next prime is 21655043231209. The reversal of 21655043231156 is 65113234055612.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3226314170 + ... + 3226320881.

It is an arithmetic number, because the mean of its divisors is an integer number (3161791175480).

Almost surely, 2^{21655043231156} is an apocalyptic number.

It is an amenable number.

21655043231156 is a deficient number, since it is larger than the sum of its proper divisors (16286450874604).

21655043231156 is a wasteful number, since it uses less digits than its factorization.

21655043231156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6452635894 (or 6452635892 counting only the distinct ones).

The product of its (nonzero) digits is 648000, while the sum is 44.

Adding to 21655043231156 its reverse (65113234055612), we get a palindrome (86768277286768).

The spelling of 21655043231156 in words is "twenty-one trillion, six hundred fifty-five billion, forty-three million, two hundred thirty-one thousand, one hundred fifty-six".