661812101325 has 72 divisors (see below), whose sum is σ = 1204096682880. Its totient is φ = 347424422400.

The previous prime is 661812101323. The next prime is 661812101341. The reversal of 661812101325 is 523101218166.

661812101325 is a `hidden beast` number, since 6 + 618 + 1 + 2 + 1 + 0 + 1 + 32 + 5 = 666.

It is not a de Polignac number, because 661812101325 - 2¹ = 661812101323 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 661812101325.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661812101323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 4995541 + ... + 5126309.

It is an arithmetic number, because the mean of its divisors is an integer number (16723565040).

Almost surely, 2^661812101325 is an apocalyptic number.

It is an amenable number.

661812101325 is a deficient number, since it is larger than the sum of its proper divisors (542284581555).

661812101325 is a wasteful number, since it uses less digits than its factorization.

661812101325 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131139 (or 131131 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The spelling of 661812101325 in words is "six hundred sixty-one billion, eight hundred twelve million, one hundred one thousand, three hundred twenty-five".