20601615861 has 6 divisors (see below), whose sum is σ = 29757889590. Its totient is φ = 13734410568.

The previous prime is 20601615857. The next prime is 20601615877. The reversal of 20601615861 is 16851610602.

20601615861 is a `hidden beast` number, since 2 + 0 + 60 + 16 + 1 + 586 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 17048263761 + 3553352100 = 130569^2 + 59610^2 .

It is not a de Polignac number, because 20601615861 - 2² = 20601615857 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20601613861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1144534206 + ... + 1144534223.

It is an arithmetic number, because the mean of its divisors is an integer number (4959648265).

Almost surely, 2^20601615861 is an apocalyptic number.

It is an amenable number.

20601615861 is a deficient number, since it is larger than the sum of its proper divisors (9156273729).

20601615861 is a wasteful number, since it uses less digits than its factorization.

20601615861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2289068435 (or 2289068432 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The spelling of 20601615861 in words is "twenty billion, six hundred one million, six hundred fifteen thousand, eight hundred sixty-one".