645772722 has 32 divisors (see below), whose sum is σ = 1553740800. Its totient is φ = 174795408.

The previous prime is 645772669. The next prime is 645772793. The reversal of 645772722 is 227277546.

It is a happy number.

It is a super-3 number, since 3×645772722³ (a number of 27 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 403822 + ... + 405417.

It is an arithmetic number, because the mean of its divisors is an integer number (48554400).

Almost surely, 2^645772722 is an apocalyptic number.

645772722 is an abundant number, since it is smaller than the sum of its proper divisors (907968078).

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

645772722 is a wasteful number, since it uses less digits than its factorization.

645772722 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 809270.

The product of its digits is 329280, while the sum is 42.

The square root of 645772722 is about 25412.0585942973. The cubic root of 645772722 is about 864.3571563309.

The spelling of 645772722 in words is "six hundred forty-five million, seven hundred seventy-two thousand, seven hundred twenty-two".