20516791 has 2 divisors, whose sum is σ = 20516792. Its totient is φ = 20516790.

The previous prime is 20516753. The next prime is 20516803. The reversal of 20516791 is 19761502.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20516791 - 2¹¹ = 20514743 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20516591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10258395 + 10258396.

It is an arithmetic number, because the mean of its divisors is an integer number (10258396).

Almost surely, 2^20516791 is an apocalyptic number.

20516791 is a deficient number, since it is larger than the sum of its proper divisors (1).

20516791 is an equidigital number, since it uses as much as digits as its factorization.

20516791 is an odious number, because the sum of its binary digits is odd.

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

The square root of 20516791 is about 4529.5464452857. The cubic root of 20516791 is about 273.7598860785.

The spelling of 20516791 in words is "twenty million, five hundred sixteen thousand, seven hundred ninety-one".