625131661 has 48 divisors (see below), whose sum is σ = 821456640. Its totient is φ = 470171520.

The previous prime is 625131653. The next prime is 625131679. The reversal of 625131661 is 166131526.

It is not a de Polignac number, because 625131661 - 2³ = 625131653 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (625131691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2256655 + ... + 2256931.

It is an arithmetic number, because the mean of its divisors is an integer number (17113680).

Almost surely, 2^625131661 is an apocalyptic number.

It is an amenable number.

625131661 is a deficient number, since it is larger than the sum of its proper divisors (196324979).

625131661 is a wasteful number, since it uses less digits than its factorization.

625131661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 434 (or 427 counting only the distinct ones).

The product of its digits is 6480, while the sum is 31.

The square root of 625131661 is about 25002.6330813377. The cubic root of 625131661 is about 855.0480056946.

The spelling of 625131661 in words is "six hundred twenty-five million, one hundred thirty-one thousand, six hundred sixty-one".