639345460 has 48 divisors (see below), whose sum is σ = 1452519936. Its totient is φ = 234986112.

The previous prime is 639345449. The next prime is 639345463. The reversal of 639345460 is 64543936.

It is a super-2 number, since 2×639345460² = 817525234445223200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639345463) 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, 52467 + ... + 63493.

It is an arithmetic number, because the mean of its divisors is an integer number (30260832).

Almost surely, 2^639345460 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 639345460, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (726259968).

639345460 is an abundant number, since it is smaller than the sum of its proper divisors (813174476).

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

639345460 is a wasteful number, since it uses less digits than its factorization.

639345460 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11272 (or 11270 counting only the distinct ones).

The product of its (nonzero) digits is 233280, while the sum is 40.

The square root of 639345460 is about 25285.2814894357. The cubic root of 639345460 is about 861.4799917026.

The spelling of 639345460 in words is "six hundred thirty-nine million, three hundred forty-five thousand, four hundred sixty".