645515437 has 24 divisors (see below), whose sum is σ = 780638976. Its totient is φ = 522629184.

The previous prime is 645515413. The next prime is 645515459. The reversal of 645515437 is 734515546.

It is a de Polignac number, because none of the positive numbers 2^k-645515437 is a prime.

It is a hoax number, since the sum of its digits (40) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 645515437.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645515407) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 275523 + ... + 277855.

It is an arithmetic number, because the mean of its divisors is an integer number (32526624).

Almost surely, 2^645515437 is an apocalyptic number.

It is an amenable number.

645515437 is a deficient number, since it is larger than the sum of its proper divisors (135123539).

645515437 is a wasteful number, since it uses less digits than its factorization.

645515437 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2445 (or 2416 counting only the distinct ones).

The product of its digits is 252000, while the sum is 40.

The square root of 645515437 is about 25406.9958279211. The cubic root of 645515437 is about 864.2423503712.

The spelling of 645515437 in words is "six hundred forty-five million, five hundred fifteen thousand, four hundred thirty-seven".