261570913 has 2 divisors, whose sum is σ = 261570914. Its totient is φ = 261570912.

The previous prime is 261570821. The next prime is 261570917. The reversal of 261570913 is 319075162.

261570913 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 222845184 + 38725729 = 14928^2 + 6223^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261570913 is a prime.

It is not a weakly prime, because it can be changed into another prime (261570917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130785456 + 130785457.

It is an arithmetic number, because the mean of its divisors is an integer number (130785457).

Almost surely, 2^261570913 is an apocalyptic number.

It is an amenable number.

261570913 is a deficient number, since it is larger than the sum of its proper divisors (1).

261570913 is an equidigital number, since it uses as much as digits as its factorization.

261570913 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11340, while the sum is 34.

The square root of 261570913 is about 16173.1540832331. The cubic root of 261570913 is about 639.5332803331.

The spelling of 261570913 in words is "two hundred sixty-one million, five hundred seventy thousand, nine hundred thirteen".