21413687 has 4 divisors (see below), whose sum is σ = 22152120. Its totient is φ = 20675256.

The previous prime is 21413677. The next prime is 21413719. The reversal of 21413687 is 78631412.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21413687 - 2¹⁰ = 21412663 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 (21413617) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 369173 + ... + 369230.

It is an arithmetic number, because the mean of its divisors is an integer number (5538030).

Almost surely, 2^21413687 is an apocalyptic number.

21413687 is a deficient number, since it is larger than the sum of its proper divisors (738433).

21413687 is an equidigital number, since it uses as much as digits as its factorization.

21413687 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 738432.

The product of its digits is 8064, while the sum is 32.

The square root of 21413687 is about 4627.4925175520. The cubic root of 21413687 is about 277.6922867165.

The spelling of 21413687 in words is "twenty-one million, four hundred thirteen thousand, six hundred eighty-seven".