21113015531 has 8 divisors (see below), whose sum is σ = 22044806304. Its totient is φ = 20182377600.

The previous prime is 21113015509. The next prime is 21113015563. The reversal of 21113015531 is 13551031112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21113015531 - 2³⁰ = 20039273707 is a prime.

It is a super-2 number, since 2×21113015531² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21113015497 and 21113015506.

It is not an unprimeable number, because it can be changed into a prime (21113015501) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 250670 + ... + 324131.

It is an arithmetic number, because the mean of its divisors is an integer number (2755600788).

Almost surely, 2^21113015531 is an apocalyptic number.

21113015531 is a deficient number, since it is larger than the sum of its proper divisors (931790773).

21113015531 is a wasteful number, since it uses less digits than its factorization.

21113015531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 576421.

The product of its (nonzero) digits is 450, while the sum is 23.

Adding to 21113015531 its reverse (13551031112), we get a palindrome (34664046643).

The spelling of 21113015531 in words is "twenty-one billion, one hundred thirteen million, fifteen thousand, five hundred thirty-one".