21113031421 has 2 divisors, whose sum is σ = 21113031422. Its totient is φ = 21113031420.

The previous prime is 21113031419. The next prime is 21113031431. The reversal of 21113031421 is 12413031112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20567575396 + 545456025 = 143414^2 + 23355^2 .

It is a cyclic number.

It is not a de Polignac number, because 21113031421 - 2¹ = 21113031419 is a prime.

Together with 21113031419, 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 (21113031431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10556515710 + 10556515711.

It is an arithmetic number, because the mean of its divisors is an integer number (10556515711).

Almost surely, 2^21113031421 is an apocalyptic number.

It is an amenable number.

21113031421 is a deficient number, since it is larger than the sum of its proper divisors (1).

21113031421 is an equidigital number, since it uses as much as digits as its factorization.

21113031421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 144, while the sum is 19.

Adding to 21113031421 its reverse (12413031112), we get a palindrome (33526062533).

The spelling of 21113031421 in words is "twenty-one billion, one hundred thirteen million, thirty-one thousand, four hundred twenty-one".