20842820 has 12 divisors (see below), whose sum is σ = 43769964. Its totient is φ = 8337120.

The previous prime is 20842817. The next prime is 20842837. The reversal of 20842820 is 2824802.

It can be written as a sum of positive squares in 2 ways, for example, as 8282884 + 12559936 = 2878^2 + 3544^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 20842820.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 521051 + ... + 521090.

It is an arithmetic number, because the mean of its divisors is an integer number (3647497).

Almost surely, 2^20842820 is an apocalyptic number.

20842820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20842820 is an abundant number, since it is smaller than the sum of its proper divisors (22927144).

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

20842820 is a wasteful number, since it uses less digits than its factorization.

20842820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1042150 (or 1042148 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 26.

The square root of 20842820 is about 4565.3937398652. The cubic root of 20842820 is about 275.2023634476.

The spelling of 20842820 in words is "twenty million, eight hundred forty-two thousand, eight hundred twenty".