20551920 has 80 divisors (see below), whose sum is σ = 67079040. Its totient is φ = 5190912.

The previous prime is 20551919. The next prime is 20551931. The reversal of 20551920 is 2915502.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2307 + ... + 6813.

It is an arithmetic number, because the mean of its divisors is an integer number (838488).

Almost surely, 2^20551920 is an apocalyptic number.

20551920 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 20551920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33539520).

20551920 is an abundant number, since it is smaller than the sum of its proper divisors (46527120).

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

20551920 is a wasteful number, since it uses less digits than its factorization.

20551920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4542 (or 4536 counting only the distinct ones).

The product of its (nonzero) digits is 900, while the sum is 24.

The square root of 20551920 is about 4533.4225481417. The cubic root of 20551920 is about 273.9160415503.

It can be divided in two parts, 205 and 51920, that added together give a palindrome (52125).

The spelling of 20551920 in words is "twenty million, five hundred fifty-one thousand, nine hundred twenty".