645744287 has 4 divisors (see below), whose sum is σ = 660761640. Its totient is φ = 630726936.

The previous prime is 645744271. The next prime is 645744299. The reversal of 645744287 is 782447546.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 782447546 = 2 ⋅391223773.

It is a cyclic number.

It is not a de Polignac number, because 645744287 - 2⁴ = 645744271 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645744487) 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, 7508612 + ... + 7508697.

It is an arithmetic number, because the mean of its divisors is an integer number (165190410).

Almost surely, 2^645744287 is an apocalyptic number.

645744287 is a deficient number, since it is larger than the sum of its proper divisors (15017353).

645744287 is a wasteful number, since it uses less digits than its factorization.

645744287 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15017352.

The product of its digits is 1505280, while the sum is 47.

The square root of 645744287 is about 25411.4991096551. The cubic root of 645744287 is about 864.3444695369.

The spelling of 645744287 in words is "six hundred forty-five million, seven hundred forty-four thousand, two hundred eighty-seven".