20179591685 has 24 divisors (see below), whose sum is σ = 28182771288. Its totient is φ = 13812761600.

The previous prime is 20179591669. The next prime is 20179591693. The reversal of 20179591685 is 58619597102.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 9980409604 + 10199182081 = 99902^2 + 100991^2 .

It is not a de Polignac number, because 20179591685 - 2⁴ = 20179591669 is a prime.

It is a super-2 number, since 2×20179591685² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 970736 + ... + 991305.

It is an arithmetic number, because the mean of its divisors is an integer number (1174282137).

Almost surely, 2^20179591685 is an apocalyptic number.

It is an amenable number.

20179591685 is a deficient number, since it is larger than the sum of its proper divisors (8003179603).

20179591685 is a wasteful number, since it uses less digits than its factorization.

20179591685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1962085 (or 1962074 counting only the distinct ones).

The product of its (nonzero) digits is 1360800, while the sum is 53.

The spelling of 20179591685 in words is "twenty billion, one hundred seventy-nine million, five hundred ninety-one thousand, six hundred eighty-five".