261619091 has 2 divisors, whose sum is σ = 261619092. Its totient is φ = 261619090.

The previous prime is 261619087. The next prime is 261619093. The reversal of 261619091 is 190916162.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261619091 - 2² = 261619087 is a prime.

Together with 261619093, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (261619093) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130809545 + 130809546.

It is an arithmetic number, because the mean of its divisors is an integer number (130809546).

Almost surely, 2^261619091 is an apocalyptic number.

261619091 is a deficient number, since it is larger than the sum of its proper divisors (1).

261619091 is an equidigital number, since it uses as much as digits as its factorization.

261619091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5832, while the sum is 35.

The square root of 261619091 is about 16174.6434582033. The cubic root of 261619091 is about 639.5725425260.

The spelling of 261619091 in words is "two hundred sixty-one million, six hundred nineteen thousand, ninety-one".