20442540 has 24 divisors (see below), whose sum is σ = 57239280. Its totient is φ = 5451328.

The previous prime is 20442523. The next prime is 20442557. The reversal of 20442540 is 4524402.

It is an interprime number because it is at equal distance from previous prime (20442523) and next prime (20442557).

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, 170295 + ... + 170414.

It is an arithmetic number, because the mean of its divisors is an integer number (2384970).

Almost surely, 2^20442540 is an apocalyptic number.

20442540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20442540 is an abundant number, since it is smaller than the sum of its proper divisors (36796740).

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

20442540 is a wasteful number, since it uses less digits than its factorization.

20442540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 340721 (or 340719 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 21.

The square root of 20442540 is about 4521.3427209182. The cubic root of 20442540 is about 273.4292379436.

Adding to 20442540 its reverse (4524402), we get a palindrome (24966942).

The spelling of 20442540 in words is "twenty million, four hundred forty-two thousand, five hundred forty".