20718780 has 48 divisors (see below), whose sum is σ = 58490880. Its totient is φ = 5479488.

The previous prime is 20718751. The next prime is 20718781. The reversal of 20718780 is 8781702.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20718781) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6261 + ... + 8979.

It is an arithmetic number, because the mean of its divisors is an integer number (1218560).

Almost surely, 2^20718780 is an apocalyptic number.

20718780 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 20718780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29245440).

20718780 is an abundant number, since it is smaller than the sum of its proper divisors (37772100).

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

20718780 is a wasteful number, since it uses less digits than its factorization.

20718780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2858 (or 2856 counting only the distinct ones).

The product of its (nonzero) digits is 6272, while the sum is 33.

The square root of 20718780 is about 4551.7886594173. The cubic root of 20718780 is about 274.6553478489.

The spelling of 20718780 in words is "twenty million, seven hundred eighteen thousand, seven hundred eighty".