21255551215603 has 2 divisors, whose sum is σ = 21255551215604. Its totient is φ = 21255551215602.

The previous prime is 21255551215559. The next prime is 21255551215631. The reversal of 21255551215603 is 30651215555212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21255551215603 - 2¹³ = 21255551207411 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21255551215603.

It is not a weakly prime, because it can be changed into another prime (21255551215643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10627775607801 + 10627775607802.

It is an arithmetic number, because the mean of its divisors is an integer number (10627775607802).

Almost surely, 2^{21255551215603} is an apocalyptic number.

21255551215603 is a deficient number, since it is larger than the sum of its proper divisors (1).

21255551215603 is an equidigital number, since it uses as much as digits as its factorization.

21255551215603 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 450000, while the sum is 43.

The spelling of 21255551215603 in words is "twenty-one trillion, two hundred fifty-five billion, five hundred fifty-one million, two hundred fifteen thousand, six hundred three".