23131540 has 24 divisors (see below), whose sum is σ = 49402080. Its totient is φ = 9095328.

The previous prime is 23131523. The next prime is 23131547. The reversal of 23131540 is 4513132.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (23131547) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8622 + ... + 10981.

It is an arithmetic number, because the mean of its divisors is an integer number (2058420).

Almost surely, 2^23131540 is an apocalyptic number.

23131540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

23131540 is an abundant number, since it is smaller than the sum of its proper divisors (26270540).

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

23131540 is a wasteful number, since it uses less digits than its factorization.

23131540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19671 (or 19669 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 23131540 is about 4809.5259641674. The cubic root of 23131540 is about 284.9278159243.

Adding to 23131540 its reverse (4513132), we get a palindrome (27644672).

The spelling of 23131540 in words is "twenty-three million, one hundred thirty-one thousand, five hundred forty".