20755780 has 24 divisors (see below), whose sum is σ = 43991640. Its totient is φ = 8225280.

The previous prime is 20755751. The next prime is 20755781. The reversal of 20755780 is 8755702.

It can be written as a sum of positive squares in 4 ways, for example, as 3048516 + 17707264 = 1746^2 + 4208^2 .

It is a hoax number, since the sum of its digits (34) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20755781) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2581 + ... + 6940.

It is an arithmetic number, because the mean of its divisors is an integer number (1832985).

Almost surely, 2^20755780 is an apocalyptic number.

20755780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20755780 is an abundant number, since it is smaller than the sum of its proper divisors (23235860).

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

20755780 is a wasteful number, since it uses less digits than its factorization.

20755780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9639 (or 9637 counting only the distinct ones).

The product of its (nonzero) digits is 19600, while the sum is 34.

The square root of 20755780 is about 4555.8511828197. The cubic root of 20755780 is about 274.8187455740.

The spelling of 20755780 in words is "twenty million, seven hundred fifty-five thousand, seven hundred eighty".