21140400430421 has 2 divisors, whose sum is σ = 21140400430422. Its totient is φ = 21140400430420.

The previous prime is 21140400430399. The next prime is 21140400430439. The reversal of 21140400430421 is 12403400404112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20502430817521 + 637969612900 = 4527961^2 + 798730^2 .

It is a cyclic number.

It is not a de Polignac number, because 21140400430421 - 2¹⁴ = 21140400414037 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21140400433421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10570200215210 + 10570200215211.

It is an arithmetic number, because the mean of its divisors is an integer number (10570200215211).

Almost surely, 2^{21140400430421} is an apocalyptic number.

It is an amenable number.

21140400430421 is a deficient number, since it is larger than the sum of its proper divisors (1).

21140400430421 is an equidigital number, since it uses as much as digits as its factorization.

21140400430421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3072, while the sum is 26.

Adding to 21140400430421 its reverse (12403400404112), we get a palindrome (33543800834533).

The spelling of 21140400430421 in words is "twenty-one trillion, one hundred forty billion, four hundred million, four hundred thirty thousand, four hundred twenty-one".