20571866685 has 24 divisors (see below), whose sum is σ = 37755427320. Its totient is φ = 10326269952.

The previous prime is 20571866639. The next prime is 20571866767. The reversal of 20571866685 is 58666817502.

It can be written as a sum of positive squares in 4 ways, for example, as 10674402489 + 9897464196 = 103317^2 + 99486^2 .

It is not a de Polignac number, because 20571866685 - 2⁹ = 20571866173 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13444900 + ... + 13446429.

It is an arithmetic number, because the mean of its divisors is an integer number (1573142805).

Almost surely, 2^20571866685 is an apocalyptic number.

It is an amenable number.

20571866685 is a deficient number, since it is larger than the sum of its proper divisors (17183560635).

20571866685 is a wasteful number, since it uses less digits than its factorization.

20571866685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26891357 (or 26891354 counting only the distinct ones).

The product of its (nonzero) digits is 4838400, while the sum is 54.

The spelling of 20571866685 in words is "twenty billion, five hundred seventy-one million, eight hundred sixty-six thousand, six hundred eighty-five".