13405515421 has 2 divisors, whose sum is σ = 13405515422. Its totient is φ = 13405515420.

The previous prime is 13405515419. The next prime is 13405515463. The reversal of 13405515421 is 12451550431.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11140802500 + 2264712921 = 105550^2 + 47589^2 .

It is a cyclic number.

It is not a de Polignac number, because 13405515421 - 2¹ = 13405515419 is a prime.

Together with 13405515419, 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 (13405515481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6702757710 + 6702757711.

It is an arithmetic number, because the mean of its divisors is an integer number (6702757711).

Almost surely, 2^13405515421 is an apocalyptic number.

It is an amenable number.

13405515421 is a deficient number, since it is larger than the sum of its proper divisors (1).

13405515421 is an equidigital number, since it uses as much as digits as its factorization.

13405515421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12000, while the sum is 31.

The spelling of 13405515421 in words is "thirteen billion, four hundred five million, five hundred fifteen thousand, four hundred twenty-one".