20779687634 has 16 divisors (see below), whose sum is σ = 31762598040. Its totient is φ = 10192216320.

The previous prime is 20779687631. The next prime is 20779687699. The reversal of 20779687634 is 43678697702.

It can be written as a sum of positive squares in 4 ways, for example, as 16153647409 + 4626040225 = 127097^2 + 68015^2 .

It is a super-2 number, since 2×20779687634² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20779687631) 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, 954794 + ... + 976314.

Almost surely, 2^20779687634 is an apocalyptic number.

20779687634 is a deficient number, since it is larger than the sum of its proper divisors (10982910406).

20779687634 is a wasteful number, since it uses less digits than its factorization.

20779687634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30685.

The product of its (nonzero) digits is 21337344, while the sum is 59.

The spelling of 20779687634 in words is "twenty billion, seven hundred seventy-nine million, six hundred eighty-seven thousand, six hundred thirty-four".