644651088 has 20 divisors (see below), whose sum is σ = 1665348768. Its totient is φ = 214883680.

The previous prime is 644651087. The next prime is 644651089. The reversal of 644651088 is 880156446.

It is an interprime number because it is at equal distance from previous prime (644651087) and next prime (644651089).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644651087) 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, 6715068 + ... + 6715163.

Almost surely, 2^644651088 is an apocalyptic number.

It is an amenable number.

644651088 is an abundant number, since it is smaller than the sum of its proper divisors (1020697680).

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

644651088 is a wasteful number, since it uses less digits than its factorization.

644651088 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13430242 (or 13430236 counting only the distinct ones).

The product of its (nonzero) digits is 184320, while the sum is 42.

The square root of 644651088 is about 25389.9800708862. The cubic root of 644651088 is about 863.8564361945.

The spelling of 644651088 in words is "six hundred forty-four million, six hundred fifty-one thousand, eighty-eight".