661899985270 has 128 divisors (see below), whose sum is σ = 1290475929600. Its totient is φ = 243644630400.

The previous prime is 661899985231. The next prime is 661899985319. The reversal of 661899985270 is 72589998166.

It is a super-2 number, since 2×661899985270² (a number of 24 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 661899985270.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1159194085 + ... + 1159194655.

It is an arithmetic number, because the mean of its divisors is an integer number (10081843200).

Almost surely, 2^661899985270 is an apocalyptic number.

661899985270 is a deficient number, since it is larger than the sum of its proper divisors (628575944330).

661899985270 is a wasteful number, since it uses less digits than its factorization.

661899985270 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1394.

The product of its (nonzero) digits is 117573120, while the sum is 70.

The spelling of 661899985270 in words is "six hundred sixty-one billion, eight hundred ninety-nine million, nine hundred eighty-five thousand, two hundred seventy".