21713869 has 4 divisors (see below), whose sum is σ = 21758944. Its totient is φ = 21668796.

The previous prime is 21713849. The next prime is 21713873. The reversal of 21713869 is 96831712.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21713869 - 2²¹ = 19616717 is a prime.

It is a super-2 number, since 2×21713869² = 942984213898322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21713819) 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, 21807 + ... + 22780.

It is an arithmetic number, because the mean of its divisors is an integer number (5439736).

Almost surely, 2^21713869 is an apocalyptic number.

It is an amenable number.

21713869 is a deficient number, since it is larger than the sum of its proper divisors (45075).

21713869 is an equidigital number, since it uses as much as digits as its factorization.

21713869 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45074.

The product of its digits is 18144, while the sum is 37.

The square root of 21713869 is about 4659.8142666849. The cubic root of 21713869 is about 278.9838550457.

The spelling of 21713869 in words is "twenty-one million, seven hundred thirteen thousand, eight hundred sixty-nine".