261278215 has 16 divisors (see below), whose sum is σ = 360040320. Its totient is φ = 180018720.

The previous prime is 261278209. The next prime is 261278221. The reversal of 261278215 is 512872162.

It is a happy number.

261278215 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (261278209) and next prime (261278221).

It is not a de Polignac number, because 261278215 - 2²³ = 252889607 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 123969 + ... + 126058.

It is an arithmetic number, because the mean of its divisors is an integer number (22502520).

Almost surely, 2^261278215 is an apocalyptic number.

261278215 is a deficient number, since it is larger than the sum of its proper divisors (98762105).

261278215 is a wasteful number, since it uses less digits than its factorization.

261278215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 250062.

The product of its digits is 13440, while the sum is 34.

The square root of 261278215 is about 16164.1026660932. The cubic root of 261278215 is about 639.2946452656.

The spelling of 261278215 in words is "two hundred sixty-one million, two hundred seventy-eight thousand, two hundred fifteen".