639774720 has 416 divisors, whose sum is σ = 2476958400. Its totient is φ = 155713536.

The previous prime is 639774697. The next prime is 639774743. The reversal of 639774720 is 27477936.

It is a happy number.

639774720 is a `hidden beast` number, since 639 + 7 + 7 + 4 + 7 + 2 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (639774697) and next prime (639774743).

It is a tau number, because it is divible by the number of its divisors (416).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7188436 + ... + 7188524.

Almost surely, 2^639774720 is an apocalyptic number.

639774720 is a gapful number since it is divisible by the number (60) 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 639774720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1238479200).

639774720 is an abundant number, since it is smaller than the sum of its proper divisors (1837183680).

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

639774720 is a wasteful number, since it uses less digits than its factorization.

639774720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140 (or 112 counting only the distinct ones).

The product of its (nonzero) digits is 444528, while the sum is 45.

The square root of 639774720 is about 25293.7684025137. The cubic root of 639774720 is about 861.6727493448.

The spelling of 639774720 in words is "six hundred thirty-nine million, seven hundred seventy-four thousand, seven hundred twenty".