645500553 has 4 divisors (see below), whose sum is σ = 860667408. Its totient is φ = 430333700.

The previous prime is 645500551. The next prime is 645500561. The reversal of 645500553 is 355005546.

645500553 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 645500553 - 2¹ = 645500551 is a prime.

It is not an unprimeable number, because it can be changed into a prime (645500551) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 107583423 + ... + 107583428.

It is an arithmetic number, because the mean of its divisors is an integer number (215166852).

Almost surely, 2^645500553 is an apocalyptic number.

It is an amenable number.

645500553 is a deficient number, since it is larger than the sum of its proper divisors (215166855).

645500553 is a wasteful number, since it uses less digits than its factorization.

645500553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 215166854.

The product of its (nonzero) digits is 45000, while the sum is 33.

The square root of 645500553 is about 25406.7029147822. The cubic root of 645500553 is about 864.2357078850.

The spelling of 645500553 in words is "six hundred forty-five million, five hundred thousand, five hundred fifty-three".