20988240 has 240 divisors, whose sum is σ = 82744704. Its totient is φ = 4285440.

The previous prime is 20988221. The next prime is 20988299. The reversal of 20988240 is 4288902.

It is a tau number, because it is divible by the number of its divisors (240).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 677025 + ... + 677055.

Almost surely, 2^20988240 is an apocalyptic number.

20988240 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 20988240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41372352).

20988240 is an abundant number, since it is smaller than the sum of its proper divisors (61756464).

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

20988240 is a wasteful number, since it uses less digits than its factorization.

20988240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98 (or 61 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 33.

The square root of 20988240 is about 4581.2923940740. The cubic root of 20988240 is about 275.8409081038.

The spelling of 20988240 in words is "twenty million, nine hundred eighty-eight thousand, two hundred forty".