645722371 has 4 divisors (see below), whose sum is σ = 737968432. Its totient is φ = 553476312.

The previous prime is 645722359. The next prime is 645722377. The reversal of 645722371 is 173227546.

It is a happy number.

645722371 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 645722371 - 2¹⁷ = 645591299 is a prime.

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 645722371.

It is not an unprimeable number, because it can be changed into a prime (645722377) 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, 46123020 + ... + 46123033.

It is an arithmetic number, because the mean of its divisors is an integer number (184492108).

Almost surely, 2^645722371 is an apocalyptic number.

645722371 is a deficient number, since it is larger than the sum of its proper divisors (92246061).

645722371 is an equidigital number, since it uses as much as digits as its factorization.

645722371 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92246060.

The product of its digits is 70560, while the sum is 37.

The square root of 645722371 is about 25411.0678838966. The cubic root of 645722371 is about 864.3346910596.

The spelling of 645722371 in words is "six hundred forty-five million, seven hundred twenty-two thousand, three hundred seventy-one".