20585461721 has 32 divisors (see below), whose sum is σ = 23962521600. Its totient is φ = 17477044480.

The previous prime is 20585461667. The next prime is 20585461759. The reversal of 20585461721 is 12716458502.

It is not a de Polignac number, because 20585461721 - 2³⁴ = 3405592537 is a prime.

It is a super-2 number, since 2×20585461721² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20585461781) 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, 16044146 + ... + 16045428.

It is an arithmetic number, because the mean of its divisors is an integer number (748828800).

Almost surely, 2^20585461721 is an apocalyptic number.

It is an amenable number.

20585461721 is a deficient number, since it is larger than the sum of its proper divisors (3377059879).

20585461721 is a wasteful number, since it uses less digits than its factorization.

20585461721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1909.

The product of its (nonzero) digits is 134400, while the sum is 41.

The spelling of 20585461721 in words is "twenty billion, five hundred eighty-five million, four hundred sixty-one thousand, seven hundred twenty-one".