215423891 has 2 divisors, whose sum is σ = 215423892. Its totient is φ = 215423890.

The previous prime is 215423863. The next prime is 215423893. The reversal of 215423891 is 198324512.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-215423891 is a prime.

Together with 215423893, 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 (215423893) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107711945 + 107711946.

It is an arithmetic number, because the mean of its divisors is an integer number (107711946).

Almost surely, 2^215423891 is an apocalyptic number.

215423891 is a deficient number, since it is larger than the sum of its proper divisors (1).

215423891 is an equidigital number, since it uses as much as digits as its factorization.

215423891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17280, while the sum is 35.

The square root of 215423891 is about 14677.3257441538. The cubic root of 215423891 is about 599.4660907832.

The spelling of 215423891 in words is "two hundred fifteen million, four hundred twenty-three thousand, eight hundred ninety-one".