261747391 has 2 divisors, whose sum is σ = 261747392. Its totient is φ = 261747390.

The previous prime is 261747377. The next prime is 261747427. The reversal of 261747391 is 193747162.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 261747391 - 2¹³ = 261739199 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261747191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130873695 + 130873696.

It is an arithmetic number, because the mean of its divisors is an integer number (130873696).

Almost surely, 2^261747391 is an apocalyptic number.

261747391 is a deficient number, since it is larger than the sum of its proper divisors (1).

261747391 is an equidigital number, since it uses as much as digits as its factorization.

261747391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 63504, while the sum is 40.

The square root of 261747391 is about 16178.6090564053. The cubic root of 261747391 is about 639.6770758594.

The spelling of 261747391 in words is "two hundred sixty-one million, seven hundred forty-seven thousand, three hundred ninety-one".