20551820 has 12 divisors (see below), whose sum is σ = 43158864. Its totient is φ = 8220720.

The previous prime is 20551819. The next prime is 20551823. The reversal of 20551820 is 2815502.

It is not an unprimeable number, because it can be changed into a prime (20551823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 513776 + ... + 513815.

It is an arithmetic number, because the mean of its divisors is an integer number (3596572).

Almost surely, 2^20551820 is an apocalyptic number.

20551820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20551820 is an abundant number, since it is smaller than the sum of its proper divisors (22607044).

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

20551820 is a wasteful number, since it uses less digits than its factorization.

20551820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1027600 (or 1027598 counting only the distinct ones).

The product of its (nonzero) digits is 800, while the sum is 23.

The square root of 20551820 is about 4533.4115189336. The cubic root of 20551820 is about 273.9155972829.

It can be divided in two parts, 205 and 51820, that added together give a palindrome (52025).

The spelling of 20551820 in words is "twenty million, five hundred fifty-one thousand, eight hundred twenty".