20712491 has 2 divisors, whose sum is σ = 20712492. Its totient is φ = 20712490.

The previous prime is 20712479. The next prime is 20712493. The reversal of 20712491 is 19421702.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20712491 is a prime.

Together with 20712493, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20712491.

It is not a weakly prime, because it can be changed into another prime (20712493) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10356245 + 10356246.

It is an arithmetic number, because the mean of its divisors is an integer number (10356246).

Almost surely, 2^20712491 is an apocalyptic number.

20712491 is a deficient number, since it is larger than the sum of its proper divisors (1).

20712491 is an equidigital number, since it uses as much as digits as its factorization.

20712491 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1008, while the sum is 26.

The square root of 20712491 is about 4551.0977796571. The cubic root of 20712491 is about 274.6275553135.

The spelling of 20712491 in words is "twenty million, seven hundred twelve thousand, four hundred ninety-one".