20639117520 has 720 divisors, whose sum is σ = 85580022528. Its totient is φ = 4607124480.

The previous prime is 20639117507. The next prime is 20639117531. The reversal of 20639117520 is 2571193602.

20639117520 is a `hidden beast` number, since 2 + 0 + 639 + 1 + 17 + 5 + 2 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (720).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 44770090 + ... + 44770550.

Almost surely, 2^20639117520 is an apocalyptic number.

20639117520 is a gapful number since it is divisible by the number (20) 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 20639117520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42790011264).

20639117520 is an abundant number, since it is smaller than the sum of its proper divisors (64940905008).

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

20639117520 is a wasteful number, since it uses less digits than its factorization.

20639117520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 550 (or 525 counting only the distinct ones).

The product of its (nonzero) digits is 22680, while the sum is 36.

The spelling of 20639117520 in words is "twenty billion, six hundred thirty-nine million, one hundred seventeen thousand, five hundred twenty".