615691897 has 4 divisors (see below), whose sum is σ = 615983220. Its totient is φ = 615400576.

The previous prime is 615691861. The next prime is 615691927. The reversal of 615691897 is 798196516.

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

It can be written as a sum of positive squares in 2 ways, for example, as 298460176 + 317231721 = 17276^2 + 17811^2 .

It is a cyclic number.

It is not a de Polignac number, because 615691897 - 2¹⁵ = 615659129 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (615691847) 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, 142468 + ... + 146725.

It is an arithmetic number, because the mean of its divisors is an integer number (153995805).

Almost surely, 2^615691897 is an apocalyptic number.

It is an amenable number.

615691897 is a deficient number, since it is larger than the sum of its proper divisors (291323).

615691897 is a wasteful number, since it uses less digits than its factorization.

615691897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 291322.

The product of its digits is 816480, while the sum is 52.

The square root of 615691897 is about 24813.1396038470. The cubic root of 615691897 is about 850.7222912463.

The spelling of 615691897 in words is "six hundred fifteen million, six hundred ninety-one thousand, eight hundred ninety-seven".