645866055 has 48 divisors (see below), whose sum is σ = 1177473024. Its totient is φ = 339564960.

The previous prime is 645866029. The next prime is 645866083. The reversal of 645866055 is 550668546.

It is a happy number.

645866055 is a `hidden beast` number, since 6 + 4 + 586 + 60 + 5 + 5 = 666.

It is not a de Polignac number, because 645866055 - 2⁹ = 645865543 is a prime.

It is a super-2 number, since 2×645866055² = 834285922002526050, which contains 22 as substring.

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

It is a self number, because there is not a number n which added to its sum of digits gives 645866055.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 82522 + ... + 90008.

It is an arithmetic number, because the mean of its divisors is an integer number (24530688).

Almost surely, 2^645866055 is an apocalyptic number.

645866055 is a deficient number, since it is larger than the sum of its proper divisors (531606969).

645866055 is an equidigital number, since it uses as much as digits as its factorization.

645866055 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7578 (or 7566 counting only the distinct ones).

The product of its (nonzero) digits is 864000, while the sum is 45.

The square root of 645866055 is about 25413.8949199055. The cubic root of 645866055 is about 864.3987959344.

The spelling of 645866055 in words is "six hundred forty-five million, eight hundred sixty-six thousand, fifty-five".