645724671 has 24 divisors (see below), whose sum is σ = 911473920. Its totient is φ = 406566864.

The previous prime is 645724669. The next prime is 645724691. The reversal of 645724671 is 176427546.

It is not a de Polignac number, because 645724671 - 2¹ = 645724669 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645724691) 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, 453066 + ... + 454488.

It is an arithmetic number, because the mean of its divisors is an integer number (37978080).

Almost surely, 2^645724671 is an apocalyptic number.

645724671 is a deficient number, since it is larger than the sum of its proper divisors (265749249).

645724671 is a wasteful number, since it uses less digits than its factorization.

645724671 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1883 (or 1864 counting only the distinct ones).

The product of its digits is 282240, while the sum is 42.

The square root of 645724671 is about 25411.1131397269. The cubic root of 645724671 is about 864.3357172836.

The spelling of 645724671 in words is "six hundred forty-five million, seven hundred twenty-four thousand, six hundred seventy-one".