615561131 has 4 divisors (see below), whose sum is σ = 619000200. Its totient is φ = 612122064.

The previous prime is 615561097. The next prime is 615561151. The reversal of 615561131 is 131165516.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-615561131 is a prime.

It is a super-2 number, since 2×615561131² = 757831011995998322, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 615561094 and 615561103.

It is not an unprimeable number, because it can be changed into a prime (615561151) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1719266 + ... + 1719623.

It is an arithmetic number, because the mean of its divisors is an integer number (154750050).

Almost surely, 2^615561131 is an apocalyptic number.

615561131 is a deficient number, since it is larger than the sum of its proper divisors (3439069).

615561131 is a wasteful number, since it uses less digits than its factorization.

615561131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3439068.

The product of its digits is 2700, while the sum is 29.

The square root of 615561131 is about 24810.5044487209. The cubic root of 615561131 is about 850.6620590488.

The spelling of 615561131 in words is "six hundred fifteen million, five hundred sixty-one thousand, one hundred thirty-one".