645433051 has 4 divisors (see below), whose sum is σ = 666253504. Its totient is φ = 624612600.

The previous prime is 645433031. The next prime is 645433091. The reversal of 645433051 is 150334546.

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

It is a cyclic number.

It is not a de Polignac number, because 645433051 - 2²⁷ = 511215323 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31), and also a Moran number because the ratio is a prime number: 20820421 = 645433051 / (6 + 4 + 5 + 4 + 3 + 3 + 0 + 5 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645433031) 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, 10410180 + ... + 10410241.

It is an arithmetic number, because the mean of its divisors is an integer number (166563376).

Almost surely, 2^645433051 is an apocalyptic number.

645433051 is a deficient number, since it is larger than the sum of its proper divisors (20820453).

645433051 is a wasteful number, since it uses less digits than its factorization.

645433051 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20820452.

The product of its (nonzero) digits is 21600, while the sum is 31.

The square root of 645433051 is about 25405.3744510881. The cubic root of 645433051 is about 864.2055815631.

Adding to 645433051 its reverse (150334546), we get a palindrome (795767597).

The spelling of 645433051 in words is "six hundred forty-five million, four hundred thirty-three thousand, fifty-one".