21969867 has 4 divisors (see below), whose sum is σ = 29293160. Its totient is φ = 14646576.

The previous prime is 21969863. The next prime is 21969869. The reversal of 21969867 is 76896912.

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

It is not a de Polignac number, because 21969867 - 2² = 21969863 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21969863) 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, 3661642 + ... + 3661647.

It is an arithmetic number, because the mean of its divisors is an integer number (7323290).

Almost surely, 2^21969867 is an apocalyptic number.

21969867 is a deficient number, since it is larger than the sum of its proper divisors (7323293).

21969867 is an equidigital number, since it uses as much as digits as its factorization.

21969867 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7323292.

The product of its digits is 326592, while the sum is 48.

The square root of 21969867 is about 4687.2024705575. The cubic root of 21969867 is about 280.0759445357.

The spelling of 21969867 in words is "twenty-one million, nine hundred sixty-nine thousand, eight hundred sixty-seven".