20815732161 has 128 divisors (see below), whose sum is σ = 38913638400. Its totient is φ = 10723415040.

The previous prime is 20815732111. The next prime is 20815732177. The reversal of 20815732161 is 16123751802.

20815732161 is a `hidden beast` number, since 2 + 0 + 8 + 1 + 573 + 21 + 61 = 666.

It is not a de Polignac number, because 20815732161 - 2⁶ = 20815732097 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20815732111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 10258095 + ... + 10260123.

It is an arithmetic number, because the mean of its divisors is an integer number (304012800).

Almost surely, 2^20815732161 is an apocalyptic number.

20815732161 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

20815732161 is a deficient number, since it is larger than the sum of its proper divisors (18097906239).

20815732161 is a wasteful number, since it uses less digits than its factorization.

20815732161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2196 (or 2190 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 36.

The spelling of 20815732161 in words is "twenty billion, eight hundred fifteen million, seven hundred thirty-two thousand, one hundred sixty-one".