665617280780 has 24 divisors (see below), whose sum is σ = 1399416020352. Its totient is φ = 265938392192.

The previous prime is 665617280753. The next prime is 665617280789. The reversal of 665617280780 is 87082716566.

It is a super-2 number, since 2×665617280780² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (665617280789) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19264817 + ... + 19299336.

It is an arithmetic number, because the mean of its divisors is an integer number (58309000848).

Almost surely, 2^665617280780 is an apocalyptic number.

It is an amenable number.

665617280780 is an abundant number, since it is smaller than the sum of its proper divisors (733798739572).

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

665617280780 is a wasteful number, since it uses less digits than its factorization.

665617280780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38565025 (or 38565023 counting only the distinct ones).

The product of its (nonzero) digits is 6773760, while the sum is 56.

The spelling of 665617280780 in words is "six hundred sixty-five billion, six hundred seventeen million, two hundred eighty thousand, seven hundred eighty".