661617788760 has 96 divisors (see below), whose sum is σ = 2164498109280. Its totient is φ = 175262976000.

The previous prime is 661617788759. The next prime is 661617788809. The reversal of 661617788760 is 67887716166.

661617788760 is a `hidden beast` number, since 6 + 6 + 1 + 617 + 7 + 8 + 8 + 7 + 6 + 0 = 666.

661617788760 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6031161 + ... + 6139880.

It is an arithmetic number, because the mean of its divisors is an integer number (22546855305).

Almost surely, 2^661617788760 is an apocalyptic number.

661617788760 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

661617788760 is an abundant number, since it is smaller than the sum of its proper divisors (1502880320520).

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

661617788760 is a wasteful number, since it uses less digits than its factorization.

661617788760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12171209 (or 12171202 counting only the distinct ones).

The product of its (nonzero) digits is 28449792, while the sum is 63.

The spelling of 661617788760 in words is "six hundred sixty-one billion, six hundred seventeen million, seven hundred eighty-eight thousand, seven hundred sixty".