645696051 has 64 divisors (see below), whose sum is σ = 1166140416. Its totient is φ = 309450240.

The previous prime is 645696047. The next prime is 645696097. The reversal of 645696051 is 150696546.

645696051 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 645696051 - 2² = 645696047 is a prime.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 645695994 and 645696012.

It is not an unprimeable number, because it can be changed into a prime (645696251) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 362475 + ... + 364251.

It is an arithmetic number, because the mean of its divisors is an integer number (18220944).

Almost surely, 2^645696051 is an apocalyptic number.

645696051 is a deficient number, since it is larger than the sum of its proper divisors (520444365).

645696051 is a wasteful number, since it uses less digits than its factorization.

645696051 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1833 (or 1811 counting only the distinct ones).

The product of its (nonzero) digits is 194400, while the sum is 42.

The square root of 645696051 is about 25410.5499940477. The cubic root of 645696051 is about 864.3229473137.

It can be divided in two parts, 645 and 696051, that added together give a palindrome (696696).

The spelling of 645696051 in words is "six hundred forty-five million, six hundred ninety-six thousand, fifty-one".