639404240000 has 160 divisors (see below), whose sum is σ = 1618747772400. Its totient is φ = 251424896000.

The previous prime is 639404239987. The next prime is 639404240029. The reversal of 639404240000 is 42404936.

639404240000 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (160).

It is a Harshad number since it is a multiple of its sum of digits (32).

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 4652267 + ... + 4787733.

Almost surely, 2^639404240000 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 639404240000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (809373886200).

639404240000 is an abundant number, since it is smaller than the sum of its proper divisors (979343532400).

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

639404240000 is an equidigital number, since it uses as much as digits as its factorization.

639404240000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135560 (or 135533 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 32.

Adding to 639404240000 its reverse (42404936), we get a palindrome (639446644936).

The spelling of 639404240000 in words is "six hundred thirty-nine billion, four hundred four million, two hundred forty thousand".