20845520 has 20 divisors (see below), whose sum is σ = 48466020. Its totient is φ = 8338176.

The previous prime is 20845511. The next prime is 20845523. The reversal of 20845520 is 2554802.

It can be written as a sum of positive squares in 2 ways, for example, as 4426816 + 16418704 = 2104^2 + 4052^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a self number, because there is not a number n which added to its sum of digits gives 20845520.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20845523) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 130205 + ... + 130364.

It is an arithmetic number, because the mean of its divisors is an integer number (2423301).

Almost surely, 2^20845520 is an apocalyptic number.

20845520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20845520 is an abundant number, since it is smaller than the sum of its proper divisors (27620500).

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

20845520 is a wasteful number, since it uses less digits than its factorization.

20845520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 260582 (or 260576 counting only the distinct ones).

The product of its (nonzero) digits is 3200, while the sum is 26.

The square root of 20845520 is about 4565.6894331525. The cubic root of 20845520 is about 275.2142462654.

The spelling of 20845520 in words is "twenty million, eight hundred forty-five thousand, five hundred twenty".