644022458 has 16 divisors (see below), whose sum is σ = 1055856384. Its totient is φ = 293292480.

The previous prime is 644022433. The next prime is 644022473. The reversal of 644022458 is 854220446.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 304460 + ... + 306567.

It is an arithmetic number, because the mean of its divisors is an integer number (65991024).

Almost surely, 2^644022458 is an apocalyptic number.

644022458 is a deficient number, since it is larger than the sum of its proper divisors (411833926).

644022458 is a wasteful number, since it uses less digits than its factorization.

644022458 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 611077.

The product of its (nonzero) digits is 61440, while the sum is 35.

The square root of 644022458 is about 25377.5975616290. The cubic root of 644022458 is about 863.5755490118.

The spelling of 644022458 in words is "six hundred forty-four million, twenty-two thousand, four hundred fifty-eight".