21121421255 has 8 divisors (see below), whose sum is σ = 27649860624. Its totient is φ = 15361033600.

The previous prime is 21121421221. The next prime is 21121421257. The reversal of 21121421255 is 55212412112.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21121421255 - 2²² = 21117226951 is a prime.

It is a super-2 number, since 2×21121421255² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121421257) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 192012866 + ... + 192012975.

It is an arithmetic number, because the mean of its divisors is an integer number (3456232578).

Almost surely, 2^21121421255 is an apocalyptic number.

21121421255 is a deficient number, since it is larger than the sum of its proper divisors (6528439369).

21121421255 is a wasteful number, since it uses less digits than its factorization.

21121421255 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 384025857.

The product of its digits is 1600, while the sum is 26.

Adding to 21121421255 its reverse (55212412112), we get a palindrome (76333833367).

The spelling of 21121421255 in words is "twenty-one billion, one hundred twenty-one million, four hundred twenty-one thousand, two hundred fifty-five".