20516431087 has 2 divisors, whose sum is σ = 20516431088. Its totient is φ = 20516431086.

The previous prime is 20516431003. The next prime is 20516431153. The reversal of 20516431087 is 78013461502.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20516431087 - 2⁷ = 20516430959 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20516431787) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10258215543 + 10258215544.

It is an arithmetic number, because the mean of its divisors is an integer number (10258215544).

Almost surely, 2^20516431087 is an apocalyptic number.

20516431087 is a deficient number, since it is larger than the sum of its proper divisors (1).

20516431087 is an equidigital number, since it uses as much as digits as its factorization.

20516431087 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40320, while the sum is 37.

Adding to 20516431087 its reverse (78013461502), we get a palindrome (98529892589).

The spelling of 20516431087 in words is "twenty billion, five hundred sixteen million, four hundred thirty-one thousand, eighty-seven".