909091861 has 2 divisors, whose sum is σ = 909091862. Its totient is φ = 909091860.

The previous prime is 909091793. The next prime is 909091877. The reversal of 909091861 is 168190909.

909091861 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 903303025 + 5788836 = 30055^2 + 2406^2 .

It is a cyclic number.

It is not a de Polignac number, because 909091861 - 2⁹ = 909091349 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (909091891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 454545930 + 454545931.

It is an arithmetic number, because the mean of its divisors is an integer number (454545931).

Almost surely, 2^909091861 is an apocalyptic number.

It is an amenable number.

909091861 is a deficient number, since it is larger than the sum of its proper divisors (1).

909091861 is an equidigital number, since it uses as much as digits as its factorization.

909091861 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 34992, while the sum is 43.

The square root of 909091861 is about 30151.1502433987. The cubic root of 909091861 is about 968.7296442702.

The spelling of 909091861 in words is "nine hundred nine million, ninety-one thousand, eight hundred sixty-one".