242640139 has 4 divisors (see below), whose sum is σ = 277303024. Its totient is φ = 207977256.

The previous prime is 242640137. The next prime is 242640149. The reversal of 242640139 is 931046242.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 242640139 - 2¹ = 242640137 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 242640139.

It is not an unprimeable number, because it can be changed into a prime (242640137) 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, 17331432 + ... + 17331445.

It is an arithmetic number, because the mean of its divisors is an integer number (69325756).

Almost surely, 2^242640139 is an apocalyptic number.

242640139 is a deficient number, since it is larger than the sum of its proper divisors (34662885).

242640139 is an equidigital number, since it uses as much as digits as its factorization.

242640139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34662884.

The product of its (nonzero) digits is 10368, while the sum is 31.

The square root of 242640139 is about 15576.9104446293. The cubic root of 242640139 is about 623.7169531476.

The spelling of 242640139 in words is "two hundred forty-two million, six hundred forty thousand, one hundred thirty-nine".