261606313 has 2 divisors, whose sum is σ = 261606314. Its totient is φ = 261606312.

The previous prime is 261606311. The next prime is 261606337. The reversal of 261606313 is 313606162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 183954969 + 77651344 = 13563^2 + 8812^2 .

It is a cyclic number.

It is not a de Polignac number, because 261606313 - 2¹ = 261606311 is a prime.

Together with 261606311, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (261606311) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130803156 + 130803157.

It is an arithmetic number, because the mean of its divisors is an integer number (130803157).

Almost surely, 2^261606313 is an apocalyptic number.

It is an amenable number.

261606313 is a deficient number, since it is larger than the sum of its proper divisors (1).

261606313 is an equidigital number, since it uses as much as digits as its factorization.

261606313 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3888, while the sum is 28.

The square root of 261606313 is about 16174.2484524011. The cubic root of 261606313 is about 639.5621296888.

The spelling of 261606313 in words is "two hundred sixty-one million, six hundred six thousand, three hundred thirteen".