16191491 has 2 divisors, whose sum is σ = 16191492. Its totient is φ = 16191490.

The previous prime is 16191457. The next prime is 16191493. The reversal of 16191491 is 19419161.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16191491 is a prime.

Together with 16191493, 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 (16191493) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8095745 + 8095746.

It is an arithmetic number, because the mean of its divisors is an integer number (8095746).

Almost surely, 2^16191491 is an apocalyptic number.

16191491 is a deficient number, since it is larger than the sum of its proper divisors (1).

16191491 is an equidigital number, since it uses as much as digits as its factorization.

16191491 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1944, while the sum is 32.

The square root of 16191491 is about 4023.8651816382. The cubic root of 16191491 is about 252.9854907915.

The spelling of 16191491 in words is "sixteen million, one hundred ninety-one thousand, four hundred ninety-one".