16720591 has 2 divisors, whose sum is σ = 16720592. Its totient is φ = 16720590.

The previous prime is 16720573. The next prime is 16720597. The reversal of 16720591 is 19502761.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 16720591 - 2¹⁷ = 16589519 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16720597) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8360295 + 8360296.

It is an arithmetic number, because the mean of its divisors is an integer number (8360296).

Almost surely, 2^16720591 is an apocalyptic number.

16720591 is a deficient number, since it is larger than the sum of its proper divisors (1).

16720591 is an equidigital number, since it uses as much as digits as its factorization.

16720591 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3780, while the sum is 31.

The square root of 16720591 is about 4089.0819263008. The cubic root of 16720591 is about 255.7116657258.

The spelling of 16720591 in words is "sixteen million, seven hundred twenty thousand, five hundred ninety-one".