20995840 has 72 divisors (see below), whose sum is σ = 51508800. Its totient is φ = 8196096.

The previous prime is 20995837. The next prime is 20995859. The reversal of 20995840 is 4859902.

It is a zygodrome in base 4.

It is a self number, because there is not a number n which added to its sum of digits gives 20995840.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 59986 + ... + 60334.

It is an arithmetic number, because the mean of its divisors is an integer number (715400).

Almost surely, 2^20995840 is an apocalyptic number.

20995840 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 20995840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25754400).

20995840 is an abundant number, since it is smaller than the sum of its proper divisors (30512960).

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

20995840 is an equidigital number, since it uses as much as digits as its factorization.

20995840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 417 (or 403 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 37.

The square root of 20995840 is about 4582.1217792634. The cubic root of 20995840 is about 275.8741987770.

The spelling of 20995840 in words is "twenty million, nine hundred ninety-five thousand, eight hundred forty".