21655431310353 has 16 divisors (see below), whose sum is σ = 30600972731520. Its totient is φ = 13575010887936.

The previous prime is 21655431310343. The next prime is 21655431310451. The reversal of 21655431310353 is 35301313455612.

It is not a de Polignac number, because 21655431310353 - 2²⁸ = 21655162874897 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21655431310313) 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, 198549925 + ... + 198658962.

It is an arithmetic number, because the mean of its divisors is an integer number (1912560795720).

Almost surely, 2^{21655431310353} is an apocalyptic number.

It is an amenable number.

21655431310353 is a deficient number, since it is larger than the sum of its proper divisors (8945541421167).

21655431310353 is a wasteful number, since it uses less digits than its factorization.

21655431310353 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 397209976.

The product of its (nonzero) digits is 486000, while the sum is 42.

Adding to 21655431310353 its reverse (35301313455612), we get a palindrome (56956744765965).

The spelling of 21655431310353 in words is "twenty-one trillion, six hundred fifty-five billion, four hundred thirty-one million, three hundred ten thousand, three hundred fifty-three".