16051991 has 2 divisors, whose sum is σ = 16051992. Its totient is φ = 16051990.

The previous prime is 16051949. The next prime is 16052027. The reversal of 16051991 is 19915061.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 16051991 - 2¹⁸ = 15789847 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16051921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8025995 + 8025996.

It is an arithmetic number, because the mean of its divisors is an integer number (8025996).

Almost surely, 2^16051991 is an apocalyptic number.

16051991 is a deficient number, since it is larger than the sum of its proper divisors (1).

16051991 is an equidigital number, since it uses as much as digits as its factorization.

16051991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2430, while the sum is 32.

The square root of 16051991 is about 4006.4936041382. The cubic root of 16051991 is about 252.2568505295.

The spelling of 16051991 in words is "sixteen million, fifty-one thousand, nine hundred ninety-one".