7561221657 has 32 divisors (see below), whose sum is σ = 11119819776. Its totient is φ = 4531982400.

The previous prime is 7561221637. The next prime is 7561221659.

It is a happy number.

7561221657 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 7561221657 - 2²⁷ = 7427003929 is a prime.

It is not an unprimeable number, because it can be changed into a prime (7561221659) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4937982 + ... + 4939512.

It is an arithmetic number, because the mean of its divisors is an integer number (347494368).

Almost surely, 2^7561221657 is an apocalyptic number.

It is an amenable number.

7561221657 is a deficient number, since it is larger than the sum of its proper divisors (3558598119).

7561221657 is a wasteful number, since it uses less digits than its factorization.

7561221657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3101.

The product of its digits is 176400, while the sum is 42.

The square root of 7561221657 is about 86955.2853885260. The cubic root of 7561221657 is about 1962.7454979074.

The spelling of 7561221657 in words is "seven billion, five hundred sixty-one million, two hundred twenty-one thousand, six hundred fifty-seven".