261439919 has 16 divisors (see below), whose sum is σ = 294743232. Its totient is φ = 230089728.

The previous prime is 261439909. The next prime is 261439921. The reversal of 261439919 is 919934162.

It is a happy number.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261439919 is a prime.

It is a super-2 number, since 2×261439919² = 136701662493453122, which contains 22 as substring.

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 261439919.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261439909) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 104309 + ... + 106785.

It is an arithmetic number, because the mean of its divisors is an integer number (18421452).

Almost surely, 2^261439919 is an apocalyptic number.

261439919 is a deficient number, since it is larger than the sum of its proper divisors (33303313).

261439919 is a wasteful number, since it uses less digits than its factorization.

261439919 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2866.

The product of its digits is 104976, while the sum is 44.

The square root of 261439919 is about 16169.1038403493. The cubic root of 261439919 is about 639.4265036657.

The spelling of 261439919 in words is "two hundred sixty-one million, four hundred thirty-nine thousand, nine hundred nineteen".