661682790 has 64 divisors (see below), whose sum is σ = 1857369600. Its totient is φ = 167160672.

The previous prime is 661682773. The next prime is 661682797. The reversal of 661682790 is 97286166.

661682790 is a `hidden beast` number, since 6 + 616 + 8 + 27 + 9 + 0 = 666.

It is a super-2 number, since 2×661682790² = 875648229164368200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661682797) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 59362 + ... + 69621.

It is an arithmetic number, because the mean of its divisors is an integer number (29021400).

Almost surely, 2^661682790 is an apocalyptic number.

661682790 is an abundant number, since it is smaller than the sum of its proper divisors (1195686810).

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

661682790 is a wasteful number, since it uses less digits than its factorization.

661682790 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129018 (or 129012 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 45.

The square root of 661682790 is about 25723.1955635376. The cubic root of 661682790 is about 871.3981087238.

The spelling of 661682790 in words is "six hundred sixty-one million, six hundred eighty-two thousand, seven hundred ninety".