21132331421 has 2 divisors, whose sum is σ = 21132331422. Its totient is φ = 21132331420.

The previous prime is 21132331403. The next prime is 21132331433. The reversal of 21132331421 is 12413323112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21087105796 + 45225625 = 145214^2 + 6725^2 .

It is a cyclic number.

It is not a de Polignac number, because 21132331421 - 2⁶ = 21132331357 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21132331471) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10566165710 + 10566165711.

It is an arithmetic number, because the mean of its divisors is an integer number (10566165711).

Almost surely, 2^21132331421 is an apocalyptic number.

It is an amenable number.

21132331421 is a deficient number, since it is larger than the sum of its proper divisors (1).

21132331421 is an equidigital number, since it uses as much as digits as its factorization.

21132331421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 864, while the sum is 23.

Adding to 21132331421 its reverse (12413323112), we get a palindrome (33545654533).

The spelling of 21132331421 in words is "twenty-one billion, one hundred thirty-two million, three hundred thirty-one thousand, four hundred twenty-one".