645540516 has 30 divisors (see below), whose sum is σ = 1687571270. Its totient is φ = 215180064.

The previous prime is 645540481. The next prime is 645540587. The reversal of 645540516 is 615045546.

645540516 is a `hidden beast` number, since 64 + 5 + 540 + 51 + 6 = 666.

It can be written as a sum of positive squares in only one way, i.e., 359254116 + 286286400 = 18954^2 + 16920^2 .

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 995881 + ... + 996528.

Almost surely, 2^645540516 is an apocalyptic number.

It is an amenable number.

645540516 is an abundant number, since it is smaller than the sum of its proper divisors (1042030754).

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

645540516 is a wasteful number, since it uses less digits than its factorization.

645540516 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1992425 (or 1992414 counting only the distinct ones).

The product of its (nonzero) digits is 72000, while the sum is 36.

The square root of 645540516 is about 25407.4893682945. The cubic root of 645540516 is about 864.2535424883.

It can be divided in two parts, 6455 and 40516, that added together give a triangular number (46971 = T₃₀₆).

The spelling of 645540516 in words is "six hundred forty-five million, five hundred forty thousand, five hundred sixteen".