616561640 has 16 divisors (see below), whose sum is σ = 1387263780. Its totient is φ = 246624640.

The previous prime is 616561637. The next prime is 616561679. The reversal of 616561640 is 46165616.

It can be written as a sum of positive squares in 2 ways, for example, as 592727716 + 23833924 = 24346^2 + 4882^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 616561640.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7706981 + ... + 7707060.

Almost surely, 2^616561640 is an apocalyptic number.

It is an amenable number.

616561640 is an abundant number, since it is smaller than the sum of its proper divisors (770702140).

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

616561640 is a wasteful number, since it uses less digits than its factorization.

616561640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15414052 (or 15414048 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 35.

The square root of 616561640 is about 24830.6592743729. The cubic root of 616561640 is about 851.1226871960.

The spelling of 616561640 in words is "six hundred sixteen million, five hundred sixty-one thousand, six hundred forty".