20205240 has 64 divisors (see below), whose sum is σ = 66130560. Its totient is φ = 4897920.

The previous prime is 20205223. The next prime is 20205259. The reversal of 20205240 is 4250202.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6334 + ... + 8973.

It is an arithmetic number, because the mean of its divisors is an integer number (1033290).

Almost surely, 2^20205240 is an apocalyptic number.

20205240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20205240 is an abundant number, since it is smaller than the sum of its proper divisors (45925320).

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

20205240 is a wasteful number, since it uses less digits than its factorization.

20205240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15332 (or 15328 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 15.

The square root of 20205240 is about 4495.0239153980. The cubic root of 20205240 is about 272.3671153007.

Adding to 20205240 its reverse (4250202), we get a palindrome (24455442).

It can be divided in two parts, 2020 and 5240, that added together give a triangular number (7260 = T₁₂₀).

The spelling of 20205240 in words is "twenty million, two hundred five thousand, two hundred forty".