1639249920 has 864 divisors, whose sum is σ = 7450606800. Its totient is φ = 340623360.

The previous prime is 1639249901. The next prime is 1639249949. The reversal of 1639249920 is 299429361.

It is a happy number.

1639249920 is a `hidden beast` number, since 1 + 639 + 2 + 4 + 9 + 9 + 2 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (864).

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 polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 149022715 + ... + 149022725.

Almost surely, 2^1639249920 is an apocalyptic number.

1639249920 is a gapful number since it is divisible by the number (10) 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 1639249920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3725303400).

1639249920 is an abundant number, since it is smaller than the sum of its proper divisors (5811356880).

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

1639249920 is a wasteful number, since it uses less digits than its factorization.

1639249920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72 (or 28 counting only the distinct ones).

The product of its (nonzero) digits is 209952, while the sum is 45.

The square root of 1639249920 is about 40487.6514507819. The cubic root of 1639249920 is about 1179.0938940690.

The spelling of 1639249920 in words is "one billion, six hundred thirty-nine million, two hundred forty-nine thousand, nine hundred twenty".