639700340 has 24 divisors (see below), whose sum is σ = 1345149960. Its totient is φ = 255541248.

The previous prime is 639700333. The next prime is 639700343. The reversal of 639700340 is 43007936.

It can be written as a sum of positive squares in 4 ways, for example, as 6574096 + 633126244 = 2564^2 + 25162^2 .

It is a super-2 number, since 2×639700340² = 818433049992231200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 639700297 and 639700306.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639700343) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5417 + ... + 36176.

It is an arithmetic number, because the mean of its divisors is an integer number (56047915).

Almost surely, 2^639700340 is an apocalyptic number.

It is an amenable number.

639700340 is an abundant number, since it is smaller than the sum of its proper divisors (705449620).

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

639700340 is a wasteful number, since it uses less digits than its factorization.

639700340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42371 (or 42369 counting only the distinct ones).

The product of its (nonzero) digits is 13608, while the sum is 32.

The square root of 639700340 is about 25292.2980371496. The cubic root of 639700340 is about 861.6393554532.

The spelling of 639700340 in words is "six hundred thirty-nine million, seven hundred thousand, three hundred forty".