561664620 has 72 divisors (see below), whose sum is σ = 1858605840. Its totient is φ = 136160640.

The previous prime is 561664619. The next prime is 561664627. The reversal of 561664620 is 26466165.

It is a happy number.

561664620 is a `hidden beast` number, since 5 + 6 + 1 + 6 + 646 + 2 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (561664627) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 139855 + ... + 143814.

It is an arithmetic number, because the mean of its divisors is an integer number (25813970).

Almost surely, 2^561664620 is an apocalyptic number.

It is an amenable number.

561664620 is an abundant number, since it is smaller than the sum of its proper divisors (1296941220).

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

561664620 is a wasteful number, since it uses less digits than its factorization.

561664620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 283695 (or 283690 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The square root of 561664620 is about 23699.4645509134. The cubic root of 561664620 is about 825.0729632439.

The spelling of 561664620 in words is "five hundred sixty-one million, six hundred sixty-four thousand, six hundred twenty".