20901840 has 160 divisors (see below), whose sum is σ = 70709760. Its totient is φ = 5087232.

The previous prime is 20901821. The next prime is 20901863. The reversal of 20901840 is 4810902.

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 20901840.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 191706 + ... + 191814.

It is an arithmetic number, because the mean of its divisors is an integer number (441936).

Almost surely, 2^20901840 is an apocalyptic number.

20901840 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 20901840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35354880).

20901840 is an abundant number, since it is smaller than the sum of its proper divisors (49807920).

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

20901840 is a wasteful number, since it uses less digits than its factorization.

20901840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 189 (or 183 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 24.

The square root of 20901840 is about 4571.8530160100. The cubic root of 20901840 is about 275.4618794580.

The spelling of 20901840 in words is "twenty million, nine hundred one thousand, eight hundred forty".