20716391 has 2 divisors, whose sum is σ = 20716392. Its totient is φ = 20716390.

The previous prime is 20716379. The next prime is 20716417. The reversal of 20716391 is 19361702.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20716391 - 2²² = 16522087 is a 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 (20716301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10358195 + 10358196.

It is an arithmetic number, because the mean of its divisors is an integer number (10358196).

Almost surely, 2^20716391 is an apocalyptic number.

20716391 is a deficient number, since it is larger than the sum of its proper divisors (1).

20716391 is an equidigital number, since it uses as much as digits as its factorization.

20716391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2268, while the sum is 29.

The square root of 20716391 is about 4551.5262275417. The cubic root of 20716391 is about 274.6447909718.

The spelling of 20716391 in words is "twenty million, seven hundred sixteen thousand, three hundred ninety-one".