661517725634 has 16 divisors (see below), whose sum is σ = 1019091560760. Its totient is φ = 321862016640.

The previous prime is 661517725607. The next prime is 661517725667. The reversal of 661517725634 is 436527715166.

It can be written as a sum of positive squares in 4 ways, for example, as 463212276409 + 198305449225 = 680597^2 + 445315^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10337369 + ... + 10401164.

Almost surely, 2^661517725634 is an apocalyptic number.

661517725634 is a deficient number, since it is larger than the sum of its proper divisors (357573835126).

661517725634 is a wasteful number, since it uses less digits than its factorization.

661517725634 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20738965.

The product of its digits is 6350400, while the sum is 53.

The spelling of 661517725634 in words is "six hundred sixty-one billion, five hundred seventeen million, seven hundred twenty-five thousand, six hundred thirty-four".