21120515015531 has 8 divisors (see below), whose sum is σ = 22232945417280. Its totient is φ = 20008167048648.

The previous prime is 21120515015449. The next prime is 21120515015591. The reversal of 21120515015531 is 13551051502112.

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 21120515015531 - 2¹⁰ = 21120515014507 is a prime.

It is a super-2 number, since 2×21120515015531² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21120515015591) 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, 20082461 + ... + 21107966.

It is an arithmetic number, because the mean of its divisors is an integer number (2779118177160).

Almost surely, 2^{21120515015531} is an apocalyptic number.

21120515015531 is a deficient number, since it is larger than the sum of its proper divisors (1112430401749).

21120515015531 is a wasteful number, since it uses less digits than its factorization.

21120515015531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41217433.

The product of its (nonzero) digits is 7500, while the sum is 32.

Adding to 21120515015531 its reverse (13551051502112), we get a palindrome (34671566517643).

The spelling of 21120515015531 in words is "twenty-one trillion, one hundred twenty billion, five hundred fifteen million, fifteen thousand, five hundred thirty-one".