661545807120 has 240 divisors, whose sum is σ = 2504641359360. Its totient is φ = 160374677760.

The previous prime is 661545807089. The next prime is 661545807193. The reversal of 661545807120 is 21708545166.

661545807120 is a `hidden beast` number, since 6 + 6 + 1 + 54 + 580 + 7 + 12 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1004224 + ... + 1526943.

It is an arithmetic number, because the mean of its divisors is an integer number (10436005664).

Almost surely, 2^661545807120 is an apocalyptic number.

661545807120 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

661545807120 is an abundant number, since it is smaller than the sum of its proper divisors (1843095552240).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

661545807120 is a wasteful number, since it uses less digits than its factorization.

661545807120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2531211 (or 2531188 counting only the distinct ones).

The product of its (nonzero) digits is 403200, while the sum is 45.

The spelling of 661545807120 in words is "six hundred sixty-one billion, five hundred forty-five million, eight hundred seven thousand, one hundred twenty".