20666688587 has 16 divisors (see below), whose sum is σ = 21589301760. Its totient is φ = 19765500768.

The previous prime is 20666688583. The next prime is 20666688589. The reversal of 20666688587 is 78588666602.

It is a cyclic number.

It is not a de Polignac number, because 20666688587 - 2² = 20666688583 is a prime.

It is a super-2 number, since 2×20666688587² (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 (20666688583) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 647948 + ... + 679094.

It is an arithmetic number, because the mean of its divisors is an integer number (1349331360).

Almost surely, 2^20666688587 is an apocalyptic number.

20666688587 is a deficient number, since it is larger than the sum of its proper divisors (922613173).

20666688587 is a wasteful number, since it uses less digits than its factorization.

20666688587 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31490.

The product of its (nonzero) digits is 46448640, while the sum is 62.

The spelling of 20666688587 in words is "twenty billion, six hundred sixty-six million, six hundred eighty-eight thousand, five hundred eighty-seven".