21400249813 has 2 divisors, whose sum is σ = 21400249814. Its totient is φ = 21400249812.

The previous prime is 21400249777. The next prime is 21400249817. The reversal of 21400249813 is 31894200412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21199942404 + 200307409 = 145602^2 + 14153^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21400249813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21400249817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10700124906 + 10700124907.

It is an arithmetic number, because the mean of its divisors is an integer number (10700124907).

Almost surely, 2^21400249813 is an apocalyptic number.

It is an amenable number.

21400249813 is a deficient number, since it is larger than the sum of its proper divisors (1).

21400249813 is an equidigital number, since it uses as much as digits as its factorization.

21400249813 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13824, while the sum is 34.

The spelling of 21400249813 in words is "twenty-one billion, four hundred million, two hundred forty-nine thousand, eight hundred thirteen".