20420902687 has 2 divisors, whose sum is σ = 20420902688. Its totient is φ = 20420902686.

The previous prime is 20420902661. The next prime is 20420902699. The reversal of 20420902687 is 78620902402.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20420902687 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20420902627) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10210451343 + 10210451344.

It is an arithmetic number, because the mean of its divisors is an integer number (10210451344).

Almost surely, 2^20420902687 is an apocalyptic number.

20420902687 is a deficient number, since it is larger than the sum of its proper divisors (1).

20420902687 is an equidigital number, since it uses as much as digits as its factorization.

20420902687 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 96768, while the sum is 40.

The spelling of 20420902687 in words is "twenty billion, four hundred twenty million, nine hundred two thousand, six hundred eighty-seven".