639872006400 has 1215 divisors, whose sum is σ = 2626535681539. Its totient is φ = 153584640000.

The previous prime is 639872006381. The next prime is 639872006479. The reversal of 639872006400 is 4600278936.

The square root of 639872006400 is 799920.

It is a perfect power (a square), and thus also a powerful number.

639872006400 is a `hidden beast` number, since 6 + 39 + 8 + 7 + 200 + 6 + 400 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 118148937984 + 521723068416 = 343728^2 + 722304^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 134 ways as a sum of consecutive naturals, for example, 6335366350 + ... + 6335366450.

Almost surely, 2^639872006400 is an apocalyptic number.

639872006400 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

639872006400 is the 799920-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 639872006400

639872006400 is an abundant number, since it is smaller than the sum of its proper divisors (1986663675139).

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

639872006400 is a wasteful number, since it uses less digits than its factorization.

639872006400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 262 (or 122 counting only the distinct ones).

The product of its (nonzero) digits is 435456, while the sum is 45.

The spelling of 639872006400 in words is "six hundred thirty-nine billion, eight hundred seventy-two million, six thousand, four hundred".