261897859 has 2 divisors, whose sum is σ = 261897860. Its totient is φ = 261897858.

The previous prime is 261897851. The next prime is 261897887. The reversal of 261897859 is 958798162.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 261897859 - 2³ = 261897851 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (261897851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130948929 + 130948930.

It is an arithmetic number, because the mean of its divisors is an integer number (130948930).

Almost surely, 2^261897859 is an apocalyptic number.

261897859 is a deficient number, since it is larger than the sum of its proper divisors (1).

261897859 is an equidigital number, since it uses as much as digits as its factorization.

261897859 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2177280, while the sum is 55.

The square root of 261897859 is about 16183.2586026424. The cubic root of 261897859 is about 639.7996272147.

The spelling of 261897859 in words is "two hundred sixty-one million, eight hundred ninety-seven thousand, eight hundred fifty-nine".