20263640 has 16 divisors (see below), whose sum is σ = 45593280. Its totient is φ = 8105440.

The previous prime is 20263637. The next prime is 20263657. The reversal of 20263640 is 4636202.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 253256 + ... + 253335.

It is an arithmetic number, because the mean of its divisors is an integer number (2849580).

Almost surely, 2^20263640 is an apocalyptic number.

20263640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20263640 is an abundant number, since it is smaller than the sum of its proper divisors (25329640).

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

20263640 is a wasteful number, since it uses less digits than its factorization.

20263640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 506602 (or 506598 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 23.

The square root of 20263640 is about 4501.5153004294. The cubic root of 20263640 is about 272.6292740161.

Adding to 20263640 its reverse (4636202), we get a palindrome (24899842).

The spelling of 20263640 in words is "twenty million, two hundred sixty-three thousand, six hundred forty".