261431139 has 8 divisors (see below), whose sum is σ = 355151952. Its totient is φ = 170998880.

The previous prime is 261431123. The next prime is 261431141. The reversal of 261431139 is 931134162.

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

It is a cyclic number.

It is not a de Polignac number, because 261431139 - 2⁴ = 261431123 is a prime.

It is not an unprimeable number, because it can be changed into a prime (261431189) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 821952 + ... + 822269.

It is an arithmetic number, because the mean of its divisors is an integer number (44393994).

Almost surely, 2^261431139 is an apocalyptic number.

261431139 is a deficient number, since it is larger than the sum of its proper divisors (93720813).

261431139 is a wasteful number, since it uses less digits than its factorization.

261431139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1644277.

The product of its digits is 3888, while the sum is 30.

The square root of 261431139 is about 16168.8323326083. The cubic root of 261431139 is about 639.4193455806.

The spelling of 261431139 in words is "two hundred sixty-one million, four hundred thirty-one thousand, one hundred thirty-nine".