261642915 has 12 divisors (see below), whose sum is σ = 453514464. Its totient is φ = 139542864.

The previous prime is 261642911. The next prime is 261642919. The reversal of 261642915 is 519246162.

261642915 is a `hidden beast` number, since 2 + 6 + 1 + 642 + 9 + 1 + 5 = 666.

It is an interprime number because it is at equal distance from previous prime (261642911) and next prime (261642919).

It is not a de Polignac number, because 261642915 - 2² = 261642911 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 261642915.

It is not an unprimeable number, because it can be changed into a prime (261642911) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2907099 + ... + 2907188.

It is an arithmetic number, because the mean of its divisors is an integer number (37792872).

Almost surely, 2^261642915 is an apocalyptic number.

261642915 is a deficient number, since it is larger than the sum of its proper divisors (191871549).

261642915 is a wasteful number, since it uses less digits than its factorization.

261642915 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5814298 (or 5814295 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 261642915 is about 16175.3799028029. The cubic root of 261642915 is about 639.5919558821.

The spelling of 261642915 in words is "two hundred sixty-one million, six hundred forty-two thousand, nine hundred fifteen".