639449616 has 80 divisors (see below), whose sum is σ = 1784635776. Its totient is φ = 196128768.

The previous prime is 639449599. The next prime is 639449633. The reversal of 639449616 is 616944936.

It is an interprime number because it is at equal distance from previous prime (639449599) and next prime (639449633).

It is a super-2 number, since 2×639449616² = 817791622805094912, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (48).

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, 218821 + ... + 221723.

Almost surely, 2^639449616 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 639449616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (892317888).

639449616 is an abundant number, since it is smaller than the sum of its proper divisors (1145186160).

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

639449616 is a wasteful number, since it uses less digits than its factorization.

639449616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3280 (or 3274 counting only the distinct ones).

The product of its digits is 839808, while the sum is 48.

The square root of 639449616 is about 25287.3410227331. The cubic root of 639449616 is about 861.5267705013.

The spelling of 639449616 in words is "six hundred thirty-nine million, four hundred forty-nine thousand, six hundred sixteen".