7561881657 has 16 divisors (see below), whose sum is σ = 12221223360. Its totient is φ = 4582958400.

The previous prime is 7561881601. The next prime is 7561881667.

7561881657 is a `hidden beast` number, since 7 + 5 + 618 + 8 + 16 + 5 + 7 = 666.

7561881657 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 7561881657 - 2²⁰ = 7560833081 is a prime.

It is not an unprimeable number, because it can be changed into a prime (7561881667) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12730144 + ... + 12730737.

It is an arithmetic number, because the mean of its divisors is an integer number (763826460).

Almost surely, 2^7561881657 is an apocalyptic number.

It is an amenable number.

7561881657 is a deficient number, since it is larger than the sum of its proper divisors (4659341703).

7561881657 is a wasteful number, since it uses less digits than its factorization.

7561881657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25460901 (or 25460895 counting only the distinct ones).

The product of its digits is 2822400, while the sum is 54.

The square root of 7561881657 is about 86959.0803596726. The cubic root of 7561881657 is about 1962.8026039501.

The spelling of 7561881657 in words is "seven billion, five hundred sixty-one million, eight hundred eighty-one thousand, six hundred fifty-seven".