21261022352015 has 16 divisors (see below), whose sum is σ = 25534744579488. Its totient is φ = 16994473681536.

The previous prime is 21261022351993. The next prime is 21261022352023. The reversal of 21261022352015 is 51025322016212.

It is a cyclic number.

It is not a de Polignac number, because 21261022352015 - 2¹⁰ = 21261022350991 is a prime.

It is a Duffinian number.

It is a congruent 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, 290243984 + ... + 290317226.

It is an arithmetic number, because the mean of its divisors is an integer number (1595921536218).

Almost surely, 2^{21261022352015} is an apocalyptic number.

21261022352015 is a deficient number, since it is larger than the sum of its proper divisors (4273722227473).

21261022352015 is a wasteful number, since it uses less digits than its factorization.

21261022352015 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121418.

The product of its (nonzero) digits is 14400, while the sum is 32.

Adding to 21261022352015 its reverse (51025322016212), we get a palindrome (72286344368227).

The spelling of 21261022352015 in words is "twenty-one trillion, two hundred sixty-one billion, twenty-two million, three hundred fifty-two thousand, fifteen".