661238736625 has 32 divisors (see below), whose sum is σ = 841514394240. Its totient is φ = 518624568000.

The previous prime is 661238736623. The next prime is 661238736667. The reversal of 661238736625 is 526637832166.

It is not a de Polignac number, because 661238736625 - 2¹ = 661238736623 is a prime.

It is a super-2 number, since 2×661238736625² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (661238736623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1580031 + ... + 1954219.

It is an arithmetic number, because the mean of its divisors is an integer number (26297324820).

Almost surely, 2^661238736625 is an apocalyptic number.

It is an amenable number.

661238736625 is a deficient number, since it is larger than the sum of its proper divisors (180275657615).

661238736625 is a wasteful number, since it uses less digits than its factorization.

661238736625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 374482 (or 374472 counting only the distinct ones).

The product of its digits is 13063680, while the sum is 55.

The spelling of 661238736625 in words is "six hundred sixty-one billion, two hundred thirty-eight million, seven hundred thirty-six thousand, six hundred twenty-five".