645965550 has 48 divisors (see below), whose sum is σ = 1779997680. Its totient is φ = 172257120.

The previous prime is 645965533. The next prime is 645965563. The reversal of 645965550 is 55569546.

645965550 is a `hidden beast` number, since 6 + 4 + 5 + 96 + 5 + 550 = 666.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

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

It is a junction number, because it is equal to n+sod(n) for n = 645965496 and 645965505.

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, 237897 + ... + 240596.

It is an arithmetic number, because the mean of its divisors is an integer number (37083285).

Almost surely, 2^645965550 is an apocalyptic number.

645965550 is an abundant number, since it is smaller than the sum of its proper divisors (1134032130).

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

645965550 is a wasteful number, since it uses less digits than its factorization.

645965550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 478514 (or 478503 counting only the distinct ones).

The product of its (nonzero) digits is 810000, while the sum is 45.

The square root of 645965550 is about 25415.8523366815. The cubic root of 645965550 is about 864.4431802365.

The spelling of 645965550 in words is "six hundred forty-five million, nine hundred sixty-five thousand, five hundred fifty".