21261203342255 has 16 divisors (see below), whose sum is σ = 26364565726464. Its totient is φ = 16442719338240.

The previous prime is 21261203342251. The next prime is 21261203342293. The reversal of 21261203342255 is 55224330216212.

It is not a de Polignac number, because 21261203342255 - 2² = 21261203342251 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21261203342251) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 73050632 + ... + 73341101.

It is an arithmetic number, because the mean of its divisors is an integer number (1647785357904).

Almost surely, 2^{21261203342255} is an apocalyptic number.

21261203342255 is a deficient number, since it is larger than the sum of its proper divisors (5103362384209).

21261203342255 is a wasteful number, since it uses less digits than its factorization.

21261203342255 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 146392706.

The product of its (nonzero) digits is 172800, while the sum is 38.

Adding to 21261203342255 its reverse (55224330216212), we get a palindrome (76485533558467).

The spelling of 21261203342255 in words is "twenty-one trillion, two hundred sixty-one billion, two hundred three million, three hundred forty-two thousand, two hundred fifty-five".