20421342246551 has 2 divisors, whose sum is σ = 20421342246552. Its totient is φ = 20421342246550.

The previous prime is 20421342246509. The next prime is 20421342246587. The reversal of 20421342246551 is 15564224312402.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20421342246551 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20421342246499 and 20421342246508.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20421342246251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10210671123275 + 10210671123276.

It is an arithmetic number, because the mean of its divisors is an integer number (10210671123276).

Almost surely, 2^{20421342246551} is an apocalyptic number.

20421342246551 is a deficient number, since it is larger than the sum of its proper divisors (1).

20421342246551 is an equidigital number, since it uses as much as digits as its factorization.

20421342246551 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 460800, while the sum is 41.

Adding to 20421342246551 its reverse (15564224312402), we get a palindrome (35985566558953).

The spelling of 20421342246551 in words is "twenty trillion, four hundred twenty-one billion, three hundred forty-two million, two hundred forty-six thousand, five hundred fifty-one".