645622749 has 12 divisors (see below), whose sum is σ = 937778400. Its totient is φ = 428009544.

The previous prime is 645622739. The next prime is 645622799. The reversal of 645622749 is 947226546.

645622749 is a `hidden beast` number, since 64 + 562 + 27 + 4 + 9 = 666.

It is not a de Polignac number, because 645622749 - 2¹² = 645618653 is a prime.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645622739) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 198769 + ... + 201990.

It is an arithmetic number, because the mean of its divisors is an integer number (78148200).

Almost surely, 2^645622749 is an apocalyptic number.

It is an amenable number.

645622749 is a deficient number, since it is larger than the sum of its proper divisors (292155651).

645622749 is a wasteful number, since it uses less digits than its factorization.

645622749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 400944 (or 400941 counting only the distinct ones).

The product of its digits is 725760, while the sum is 45.

The square root of 645622749 is about 25409.1075994416. The cubic root of 645622749 is about 864.2902389426.

The spelling of 645622749 in words is "six hundred forty-five million, six hundred twenty-two thousand, seven hundred forty-nine".