21731413 has 8 divisors (see below), whose sum is σ = 23813280. Its totient is φ = 19667280.

The previous prime is 21731377. The next prime is 21731417. The reversal of 21731413 is 31413712.

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

It is a cyclic number.

It is not a de Polignac number, because 21731413 - 2²¹ = 19634261 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21731417) 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, 1795 + ... + 6832.

It is an arithmetic number, because the mean of its divisors is an integer number (2976660).

Almost surely, 2^21731413 is an apocalyptic number.

It is an amenable number.

21731413 is a deficient number, since it is larger than the sum of its proper divisors (2081867).

21731413 is a wasteful number, since it uses less digits than its factorization.

21731413 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8867.

The product of its digits is 504, while the sum is 22.

The square root of 21731413 is about 4661.6963650585. The cubic root of 21731413 is about 279.0589710181.

The spelling of 21731413 in words is "twenty-one million, seven hundred thirty-one thousand, four hundred thirteen".