261270247 has 4 divisors (see below), whose sum is σ = 298594576. Its totient is φ = 223945920.

The previous prime is 261270239. The next prime is 261270281. The reversal of 261270247 is 742072162.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 261270247 - 2³ = 261270239 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261270047) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18662154 + ... + 18662167.

It is an arithmetic number, because the mean of its divisors is an integer number (74648644).

Almost surely, 2^261270247 is an apocalyptic number.

261270247 is a deficient number, since it is larger than the sum of its proper divisors (37324329).

261270247 is an equidigital number, since it uses as much as digits as its factorization.

261270247 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37324328.

The product of its (nonzero) digits is 9408, while the sum is 31.

The square root of 261270247 is about 16163.8561921344. The cubic root of 261270247 is about 639.2881465078.

The spelling of 261270247 in words is "two hundred sixty-one million, two hundred seventy thousand, two hundred forty-seven".