23147981 has 4 divisors (see below), whose sum is σ = 23167932. Its totient is φ = 23128032.

The previous prime is 23147963. The next prime is 23147987. The reversal of 23147981 is 18974132.

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 17926756 + 5221225 = 4234^2 + 2285^2 .

It is a cyclic number.

It is not a de Polignac number, because 23147981 - 2²² = 18953677 is a prime.

It is a super-2 number, since 2×23147981² = 1071658048752722, 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 (23147987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8120 + ... + 10593.

It is an arithmetic number, because the mean of its divisors is an integer number (5791983).

Almost surely, 2^23147981 is an apocalyptic number.

It is an amenable number.

23147981 is a deficient number, since it is larger than the sum of its proper divisors (19951).

23147981 is a wasteful number, since it uses less digits than its factorization.

23147981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19950.

The product of its digits is 12096, while the sum is 35.

The square root of 23147981 is about 4811.2348726704. The cubic root of 23147981 is about 284.9953051448.

Subtracting from 23147981 its reverse (18974132), we obtain a square (4173849 = 2043²).

The spelling of 23147981 in words is "twenty-three million, one hundred forty-seven thousand, nine hundred eighty-one".