645764730 has 32 divisors (see below), whose sum is σ = 1669054464. Its totient is φ = 158957376.

The previous prime is 645764729. The next prime is 645764731. The reversal of 645764730 is 37467546.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (645764729) and next prime (645764731).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (645764731) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 827514 + ... + 828293.

It is an arithmetic number, because the mean of its divisors is an integer number (52157952).

Almost surely, 2^645764730 is an apocalyptic number.

645764730 is an abundant number, since it is smaller than the sum of its proper divisors (1023289734).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

645764730 is a wasteful number, since it uses less digits than its factorization.

645764730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1655830.

The product of its (nonzero) digits is 423360, while the sum is 42.

The square root of 645764730 is about 25411.9013456294. The cubic root of 645764730 is about 864.3535905920.

The spelling of 645764730 in words is "six hundred forty-five million, seven hundred sixty-four thousand, seven hundred thirty".