21651560923571 has 8 divisors (see below), whose sum is σ = 21816381442800. Its totient is φ = 21486838664448.

The previous prime is 21651560923469. The next prime is 21651560923579. The reversal of 21651560923571 is 17532906515612.

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 21651560923571 - 2¹⁸ = 21651560661427 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21651560923579) 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, 24122621 + ... + 25004078.

It is an arithmetic number, because the mean of its divisors is an integer number (2727047680350).

Almost surely, 2^{21651560923571} is an apocalyptic number.

21651560923571 is a deficient number, since it is larger than the sum of its proper divisors (164820519229).

21651560923571 is a wasteful number, since it uses less digits than its factorization.

21651560923571 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49130053.

The product of its (nonzero) digits is 3402000, while the sum is 53.

The spelling of 21651560923571 in words is "twenty-one trillion, six hundred fifty-one billion, five hundred sixty million, nine hundred twenty-three thousand, five hundred seventy-one".