645464506 has 4 divisors (see below), whose sum is σ = 968196762. Its totient is φ = 322732252.

The previous prime is 645464497. The next prime is 645464527. The reversal of 645464506 is 605464546.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 455438281 + 190026225 = 21341^2 + 13785^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161366125 + ... + 161366128.

Almost surely, 2^645464506 is an apocalyptic number.

645464506 is a deficient number, since it is larger than the sum of its proper divisors (322732256).

645464506 is a wasteful number, since it uses less digits than its factorization.

645464506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322732255.

The product of its (nonzero) digits is 345600, while the sum is 40.

The square root of 645464506 is about 25405.9935054703. The cubic root of 645464506 is about 864.2196202745.

Adding to 645464506 its sum of digits (40), we get a palindrome (645464546).

The spelling of 645464506 in words is "six hundred forty-five million, four hundred sixty-four thousand, five hundred six".