23981538 has 64 divisors (see below), whose sum is σ = 57434112. Its totient is φ = 6531840.

The previous prime is 23981533. The next prime is 23981563. The reversal of 23981538 is 83518932.

It is a super-2 number, since 2×23981538² = 1150228329690888, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 23981496 and 23981505.

It is not an unprimeable number, because it can be changed into a prime (23981533) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 147045 + ... + 147207.

It is an arithmetic number, because the mean of its divisors is an integer number (897408).

Almost surely, 2^23981538 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 23981538, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28717056).

23981538 is an abundant number, since it is smaller than the sum of its proper divisors (33452574).

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

23981538 is a wasteful number, since it uses less digits than its factorization.

23981538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 319.

The product of its digits is 51840, while the sum is 39.

The square root of 23981538 is about 4897.0948530736. The cubic root of 23981538 is about 288.3759317225.

The spelling of 23981538 in words is "twenty-three million, nine hundred eighty-one thousand, five hundred thirty-eight".