661786541570 has 64 divisors (see below), whose sum is σ = 1503951667200. Its totient is φ = 203660084160.

The previous prime is 661786541567. The next prime is 661786541597. The reversal of 661786541570 is 75145687166.

It is a happy number.

It is a super-2 number, since 2×661786541570² (a number of 24 digits) contains 22 as substring.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 5378810 + ... + 5500469.

It is an arithmetic number, because the mean of its divisors is an integer number (23499244800).

Almost surely, 2^661786541570 is an apocalyptic number.

661786541570 is an abundant number, since it is smaller than the sum of its proper divisors (842165125630).

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

661786541570 is a wasteful number, since it uses less digits than its factorization.

661786541570 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10879383.

The product of its (nonzero) digits is 8467200, while the sum is 56.

The spelling of 661786541570 in words is "six hundred sixty-one billion, seven hundred eighty-six million, five hundred forty-one thousand, five hundred seventy".