239640981 has 4 divisors (see below), whose sum is σ = 319521312. Its totient is φ = 159760652.

The previous prime is 239640953. The next prime is 239640997. The reversal of 239640981 is 189046932.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 239640981 - 2⁶ = 239640917 is a prime.

It is a super-2 number, since 2×239640981² = 114855599549284722, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (239640911) 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, 39940161 + ... + 39940166.

It is an arithmetic number, because the mean of its divisors is an integer number (79880328).

Almost surely, 2^239640981 is an apocalyptic number.

It is an amenable number.

239640981 is a deficient number, since it is larger than the sum of its proper divisors (79880331).

239640981 is an equidigital number, since it uses as much as digits as its factorization.

239640981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79880330.

The product of its (nonzero) digits is 93312, while the sum is 42.

The square root of 239640981 is about 15480.3417597933. The cubic root of 239640981 is about 621.1364700164.

The spelling of 239640981 in words is "two hundred thirty-nine million, six hundred forty thousand, nine hundred eighty-one".