21217576660761 has 32 divisors (see below), whose sum is σ = 31546813979520. Its totient is φ = 12594734208000.

The previous prime is 21217576660757. The next prime is 21217576660811. The reversal of 21217576660761 is 16706667571212.

It is not a de Polignac number, because 21217576660761 - 2² = 21217576660757 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21217576660711) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7736160 + ... + 10113521.

It is an arithmetic number, because the mean of its divisors is an integer number (985837936860).

Almost surely, 2^{21217576660761} is an apocalyptic number.

It is an amenable number.

21217576660761 is a deficient number, since it is larger than the sum of its proper divisors (10329237318759).

21217576660761 is a wasteful number, since it uses less digits than its factorization.

21217576660761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17850777.

The product of its (nonzero) digits is 8890560, while the sum is 57.

The spelling of 21217576660761 in words is "twenty-one trillion, two hundred seventeen billion, five hundred seventy-six million, six hundred sixty thousand, seven hundred sixty-one".