644482734 has 32 divisors (see below), whose sum is σ = 1474676736. Its totient is φ = 183941280.

The previous prime is 644482697. The next prime is 644482739. The reversal of 644482734 is 437284446.

It is a happy number.

It is a super-2 number, since 2×644482734² = 830715988848229512, which contains 22 as substring.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644482739) 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, 34179 + ... + 49569.

It is an arithmetic number, because the mean of its divisors is an integer number (46083648).

Almost surely, 2^644482734 is an apocalyptic number.

644482734 is an abundant number, since it is smaller than the sum of its proper divisors (830194002).

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

644482734 is a wasteful number, since it uses less digits than its factorization.

644482734 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16400.

The product of its digits is 516096, while the sum is 42.

The square root of 644482734 is about 25386.6644914215. The cubic root of 644482734 is about 863.7812294399.

The spelling of 644482734 in words is "six hundred forty-four million, four hundred eighty-two thousand, seven hundred thirty-four".