625491866161 has 4 divisors (see below), whose sum is σ = 633409484800. Its totient is φ = 617574247524.

The previous prime is 625491866123. The next prime is 625491866171. The reversal of 625491866161 is 161668194526.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 625491866161 - 2³¹ = 623344382513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (625491866171) 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, 3958809201 + ... + 3958809358.

It is an arithmetic number, because the mean of its divisors is an integer number (158352371200).

Almost surely, 2^625491866161 is an apocalyptic number.

It is an amenable number.

625491866161 is a deficient number, since it is larger than the sum of its proper divisors (7917618639).

625491866161 is an equidigital number, since it uses as much as digits as its factorization.

625491866161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7917618638.

The product of its digits is 3732480, while the sum is 55.

The spelling of 625491866161 in words is "six hundred twenty-five billion, four hundred ninety-one million, eight hundred sixty-six thousand, one hundred sixty-one".