20994785280 has 680 divisors, whose sum is σ = 86783681952. Its totient is φ = 4756340736.

The previous prime is 20994785269. The next prime is 20994785299. The reversal of 20994785280 is 8258749902.

20994785280 is a `hidden beast` number, since 2 + 0 + 99 + 478 + 5 + 2 + 80 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a Saint-Exupery number, since it is equal to the product of the sides of a Pythagorean triangle: 5424 × 720 × 5376.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 185794504 + ... + 185794616.

Almost surely, 2^20994785280 is an apocalyptic number.

20994785280 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 20994785280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43391840976).

20994785280 is an abundant number, since it is smaller than the sum of its proper divisors (65788896672).

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

20994785280 is an frugal number, since it uses more digits than its factorization.

20994785280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169 (or 130 counting only the distinct ones).

The product of its (nonzero) digits is 2903040, while the sum is 54.

The spelling of 20994785280 in words is "twenty billion, nine hundred ninety-four million, seven hundred eighty-five thousand, two hundred eighty".