639667392 has 224 divisors, whose sum is σ = 2152034304. Its totient is φ = 163123200.

The previous prime is 639667337. The next prime is 639667397. The reversal of 639667392 is 293766936.

It is a tau number, because it is divible by the number of its divisors (224).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639667397) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 541042 + ... + 542222.

It is an arithmetic number, because the mean of its divisors is an integer number (9607296).

Almost surely, 2^639667392 is an apocalyptic number.

639667392 is a gapful number since it is divisible by the number (62) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 639667392, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1076017152).

639667392 is an abundant number, since it is smaller than the sum of its proper divisors (1512366912).

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

639667392 is a wasteful number, since it uses less digits than its factorization.

639667392 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1247 (or 1237 counting only the distinct ones).

The product of its digits is 2204496, while the sum is 51.

The square root of 639667392 is about 25291.6466842315. The cubic root of 639667392 is about 861.6245621825.

The spelling of 639667392 in words is "six hundred thirty-nine million, six hundred sixty-seven thousand, three hundred ninety-two".