21620555503 has 2 divisors, whose sum is σ = 21620555504. Its totient is φ = 21620555502.

The previous prime is 21620555501. The next prime is 21620555521. The reversal of 21620555503 is 30555502612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21620555503 - 2¹ = 21620555501 is a prime.

Together with 21620555501, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21620555501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10810277751 + 10810277752.

It is an arithmetic number, because the mean of its divisors is an integer number (10810277752).

Almost surely, 2^21620555503 is an apocalyptic number.

21620555503 is a deficient number, since it is larger than the sum of its proper divisors (1).

21620555503 is an equidigital number, since it uses as much as digits as its factorization.

21620555503 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 45000, while the sum is 34.

The spelling of 21620555503 in words is "twenty-one billion, six hundred twenty million, five hundred fifty-five thousand, five hundred three".