661899985268 has 48 divisors (see below), whose sum is σ = 1201848904704. Its totient is φ = 318627717120.

The previous prime is 661899985231. The next prime is 661899985319. The reversal of 661899985268 is 862589998166.

It is a super-2 number, since 2×661899985268² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26214746 + ... + 26239982.

It is an arithmetic number, because the mean of its divisors is an integer number (25038518848).

Almost surely, 2^661899985268 is an apocalyptic number.

It is an amenable number.

661899985268 is a deficient number, since it is larger than the sum of its proper divisors (539948919436).

661899985268 is a wasteful number, since it uses less digits than its factorization.

661899985268 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26352 (or 26350 counting only the distinct ones).

The product of its digits is 806215680, while the sum is 77.

The spelling of 661899985268 in words is "six hundred sixty-one billion, eight hundred ninety-nine million, nine hundred eighty-five thousand, two hundred sixty-eight".