239909981 has 8 divisors (see below), whose sum is σ = 242440440. Its totient is φ = 237385728.

The previous prime is 239909939. The next prime is 239910019. The reversal of 239909981 is 189909932.

It can be written as a sum of positive squares in 4 ways, for example, as 200647225 + 39262756 = 14165^2 + 6266^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-239909981 is a prime.

It is a super-2 number, since 2×239909981² = 115113597966840722, 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 (239909911) 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, 140525 + ... + 142221.

It is an arithmetic number, because the mean of its divisors is an integer number (30305055).

Almost surely, 2^239909981 is an apocalyptic number.

It is an amenable number.

239909981 is a deficient number, since it is larger than the sum of its proper divisors (2530459).

239909981 is a wasteful number, since it uses less digits than its factorization.

239909981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3103.

The product of its (nonzero) digits is 314928, while the sum is 50.

The square root of 239909981 is about 15489.0277616124. The cubic root of 239909981 is about 621.3687942626.

The spelling of 239909981 in words is "two hundred thirty-nine million, nine hundred nine thousand, nine hundred eighty-one".