261679290 has 16 divisors (see below), whose sum is σ = 628030368. Its totient is φ = 69781136.

The previous prime is 261679289. The next prime is 261679291. The reversal of 261679290 is 92976162.

It is an interprime number because it is at equal distance from previous prime (261679289) and next prime (261679291).

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (261679291) 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, 4361292 + ... + 4361351.

It is an arithmetic number, because the mean of its divisors is an integer number (39251898).

Almost surely, 2^261679290 is an apocalyptic number.

261679290 is an abundant number, since it is smaller than the sum of its proper divisors (366351078).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261679290 is a wasteful number, since it uses less digits than its factorization.

261679290 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8722653.

The product of its (nonzero) digits is 81648, while the sum is 42.

The square root of 261679290 is about 16176.5042577190. The cubic root of 261679290 is about 639.6215943423.

The spelling of 261679290 in words is "two hundred sixty-one million, six hundred seventy-nine thousand, two hundred ninety".