2161636731 has 6 divisors (see below), whose sum is σ = 3122364180. Its totient is φ = 1441091148.

The previous prime is 2161636723. The next prime is 2161636739. The reversal of 2161636731 is 1376361612.

2161636731 is a `hidden beast` number, since 2 + 1 + 616 + 3 + 6 + 7 + 31 = 666.

It is an interprime number because it is at equal distance from previous prime (2161636723) and next prime (2161636739).

It is not a de Polignac number, because 2161636731 - 2³ = 2161636723 is a prime.

It is a super-2 number, since 2×2161636731² = 9345346713616732722, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (2161636739) 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 5 ways as a sum of consecutive naturals, for example, 120090921 + ... + 120090938.

It is an arithmetic number, because the mean of its divisors is an integer number (520394030).

Almost surely, 2^2161636731 is an apocalyptic number.

2161636731 is a deficient number, since it is larger than the sum of its proper divisors (960727449).

2161636731 is a wasteful number, since it uses less digits than its factorization.

2161636731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 240181865 (or 240181862 counting only the distinct ones).

The product of its digits is 27216, while the sum is 36.

The square root of 2161636731 is about 46493.4052420341. The cubic root of 2161636731 is about 1292.9872343670.

The spelling of 2161636731 in words is "two billion, one hundred sixty-one million, six hundred thirty-six thousand, seven hundred thirty-one".