644481677 has 16 divisors (see below), whose sum is σ = 746054400. Its totient is φ = 545315328.

The previous prime is 644481667. The next prime is 644481731. The reversal of 644481677 is 776184446.

It is not a de Polignac number, because 644481677 - 2⁶ = 644481613 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644481667) 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, 329699 + ... + 331647.

It is an arithmetic number, because the mean of its divisors is an integer number (46628400).

Almost surely, 2^644481677 is an apocalyptic number.

It is an amenable number.

644481677 is a deficient number, since it is larger than the sum of its proper divisors (101572723).

644481677 is a wasteful number, since it uses less digits than its factorization.

644481677 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2540.

The product of its digits is 903168, while the sum is 47.

The square root of 644481677 is about 25386.6436733964. The cubic root of 644481677 is about 863.7807572177.

The spelling of 644481677 in words is "six hundred forty-four million, four hundred eighty-one thousand, six hundred seventy-seven".