20519491 has 2 divisors, whose sum is σ = 20519492. Its totient is φ = 20519490.

The previous prime is 20519461. The next prime is 20519507. The reversal of 20519491 is 19491502.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20519491 is a prime.

It is not a weakly prime, because it can be changed into another prime (20519441) 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, 10259745 + 10259746.

It is an arithmetic number, because the mean of its divisors is an integer number (10259746).

Almost surely, 2^20519491 is an apocalyptic number.

20519491 is a deficient number, since it is larger than the sum of its proper divisors (1).

20519491 is an equidigital number, since it uses as much as digits as its factorization.

20519491 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3240, while the sum is 31.

The square root of 20519491 is about 4529.8444785666. The cubic root of 20519491 is about 273.7718944423.

The spelling of 20519491 in words is "twenty million, five hundred nineteen thousand, four hundred ninety-one".