21331064155 has 16 divisors (see below), whose sum is σ = 25942234464. Its totient is φ = 16836076800.

The previous prime is 21331064149. The next prime is 21331064171. The reversal of 21331064155 is 55146013312.

It is not a de Polignac number, because 21331064155 - 2¹⁵ = 21331031387 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 68287 + ... + 217543.

It is an arithmetic number, because the mean of its divisors is an integer number (1621389654).

Almost surely, 2^21331064155 is an apocalyptic number.

21331064155 is a deficient number, since it is larger than the sum of its proper divisors (4611170309).

21331064155 is a wasteful number, since it uses less digits than its factorization.

21331064155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149646.

The product of its (nonzero) digits is 10800, while the sum is 31.

Adding to 21331064155 its reverse (55146013312), we get a palindrome (76477077467).

The spelling of 21331064155 in words is "twenty-one billion, three hundred thirty-one million, sixty-four thousand, one hundred fifty-five".