20550840 has 64 divisors (see below), whose sum is σ = 63171360. Its totient is φ = 5345280.

The previous prime is 20550809. The next prime is 20550857. The reversal of 20550840 is 4805502.

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

It is a self number, because there is not a number n which added to its sum of digits gives 20550840.

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, 2832 + ... + 7008.

Almost surely, 2^20550840 is an apocalyptic number.

20550840 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 20550840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31585680).

20550840 is an abundant number, since it is smaller than the sum of its proper divisors (42620520).

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

20550840 is a wasteful number, since it uses less digits than its factorization.

20550840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4232 (or 4228 counting only the distinct ones).

The product of its (nonzero) digits is 1600, while the sum is 24.

The square root of 20550840 is about 4533.3034312739. The cubic root of 20550840 is about 273.9112433854.

The spelling of 20550840 in words is "twenty million, five hundred fifty thousand, eight hundred forty".