20442240 has 384 divisors, whose sum is σ = 89596800. Its totient is φ = 4313088.

The previous prime is 20442203. The next prime is 20442269. The reversal of 20442240 is 4224402.

20442240 is a `hidden beast` number, since 204 + 422 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (384).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.

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, 1572474 + ... + 1572486.

It is an arithmetic number, because the mean of its divisors is an integer number (233325).

Almost surely, 2^20442240 is an apocalyptic number.

20442240 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 20442240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44798400).

20442240 is an abundant number, since it is smaller than the sum of its proper divisors (69154560).

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

20442240 is a wasteful number, since it uses less digits than its factorization.

20442240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61 (or 30 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 18.

The square root of 20442240 is about 4521.3095448111. The cubic root of 20442240 is about 273.4279003868.

Adding to 20442240 its reverse (4224402), we get a palindrome (24666642).

The spelling of 20442240 in words is "twenty million, four hundred forty-two thousand, two hundred forty".