13431821 has 8 divisors (see below), whose sum is σ = 14559384. Its totient is φ = 12317760.

The previous prime is 13431811. The next prime is 13431857. The reversal of 13431821 is 12813431.

13431821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 28900 + 13402921 = 170^2 + 3661^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 13431821 - 2⁶ = 13431757 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13431811) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1250 + ... + 5331.

It is an arithmetic number, because the mean of its divisors is an integer number (1819923).

Almost surely, 2^13431821 is an apocalyptic number.

It is an amenable number.

13431821 is a deficient number, since it is larger than the sum of its proper divisors (1127563).

13431821 is a wasteful number, since it uses less digits than its factorization.

13431821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6751.

The product of its digits is 576, while the sum is 23.

The square root of 13431821 is about 3664.9448836238. The cubic root of 13431821 is about 237.7086388221.

The spelling of 13431821 in words is "thirteen million, four hundred thirty-one thousand, eight hundred twenty-one".