20756820 has 96 divisors (see below), whose sum is σ = 67431168. Its totient is φ = 4672512.

The previous prime is 20756809. The next prime is 20756839. The reversal of 20756820 is 2865702.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 30322 + ... + 30998.

It is an arithmetic number, because the mean of its divisors is an integer number (702408).

Almost surely, 2^20756820 is an apocalyptic number.

20756820 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 20756820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33715584).

20756820 is an abundant number, since it is smaller than the sum of its proper divisors (46674348).

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

20756820 is a wasteful number, since it uses less digits than its factorization.

20756820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 769 (or 767 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 30.

The square root of 20756820 is about 4555.9653203246. The cubic root of 20756820 is about 274.8233355680.

The spelling of 20756820 in words is "twenty million, seven hundred fifty-six thousand, eight hundred twenty".