23783981 has 4 divisors (see below), whose sum is σ = 25613532. Its totient is φ = 21954432.

The previous prime is 23783971. The next prime is 23783993. The reversal of 23783981 is 18938732.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2669956 + 21114025 = 1634^2 + 4595^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-23783981 is a prime.

It is a super-2 number, since 2×23783981² = 1131355504416722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (23783951) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 914756 + ... + 914781.

It is an arithmetic number, because the mean of its divisors is an integer number (6403383).

Almost surely, 2^23783981 is an apocalyptic number.

It is an amenable number.

23783981 is a deficient number, since it is larger than the sum of its proper divisors (1829551).

23783981 is a wasteful number, since it uses less digits than its factorization.

23783981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1829550.

The product of its digits is 72576, while the sum is 41.

The square root of 23783981 is about 4876.8823032753. The cubic root of 23783981 is about 287.5818786325.

The spelling of 23783981 in words is "twenty-three million, seven hundred eighty-three thousand, nine hundred eighty-one".