261639137 has 8 divisors (see below), whose sum is σ = 263233152. Its totient is φ = 260050000.

The previous prime is 261639113. The next prime is 261639149. The reversal of 261639137 is 731936162.

It is a happy number.

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-261639137 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 261639137.

It is not an unprimeable number, because it can be changed into a prime (261639337) 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, 175208 + ... + 176694.

It is an arithmetic number, because the mean of its divisors is an integer number (32904144).

Almost surely, 2^261639137 is an apocalyptic number.

It is an amenable number.

261639137 is a deficient number, since it is larger than the sum of its proper divisors (1594015).

261639137 is a wasteful number, since it uses less digits than its factorization.

261639137 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2439.

The product of its digits is 40824, while the sum is 38.

The square root of 261639137 is about 16175.2631199619. The cubic root of 261639137 is about 639.5888773988.

The spelling of 261639137 in words is "two hundred sixty-one million, six hundred thirty-nine thousand, one hundred thirty-seven".