21696447 has 8 divisors (see below), whose sum is σ = 29003056. Its totient is φ = 14427072.

The previous prime is 21696443. The next prime is 21696457. The reversal of 21696447 is 74469612.

It is a happy number.

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

It is not a de Polignac number, because 21696447 - 2² = 21696443 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 (21696443) 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, 7918 + ... + 10299.

It is an arithmetic number, because the mean of its divisors is an integer number (3625382).

Almost surely, 2^21696447 is an apocalyptic number.

21696447 is a deficient number, since it is larger than the sum of its proper divisors (7306609).

21696447 is a wasteful number, since it uses less digits than its factorization.

21696447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18617.

The product of its digits is 72576, while the sum is 39.

The square root of 21696447 is about 4657.9445037484. The cubic root of 21696447 is about 278.9092213753.

The spelling of 21696447 in words is "twenty-one million, six hundred ninety-six thousand, four hundred forty-seven".