261613397 has 2 divisors, whose sum is σ = 261613398. Its totient is φ = 261613396.

The previous prime is 261613301. The next prime is 261613399. The reversal of 261613397 is 793316162.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 230766481 + 30846916 = 15191^2 + 5554^2 .

It is a cyclic number.

It is not a de Polignac number, because 261613397 - 2¹² = 261609301 is a prime.

Together with 261613399, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 261613397.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261613399) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130806698 + 130806699.

It is an arithmetic number, because the mean of its divisors is an integer number (130806699).

Almost surely, 2^261613397 is an apocalyptic number.

It is an amenable number.

261613397 is a deficient number, since it is larger than the sum of its proper divisors (1).

261613397 is an equidigital number, since it uses as much as digits as its factorization.

261613397 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 40824, while the sum is 38.

The square root of 261613397 is about 16174.4674410010. The cubic root of 261613397 is about 639.5679025072.

The spelling of 261613397 in words is "two hundred sixty-one million, six hundred thirteen thousand, three hundred ninety-seven".