21884691 has 4 divisors (see below), whose sum is σ = 29179592. Its totient is φ = 14589792.

The previous prime is 21884689. The next prime is 21884699. The reversal of 21884691 is 19648812.

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

It is not a de Polignac number, because 21884691 - 2¹ = 21884689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21884699) 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, 3647446 + ... + 3647451.

It is an arithmetic number, because the mean of its divisors is an integer number (7294898).

Almost surely, 2^21884691 is an apocalyptic number.

21884691 is a deficient number, since it is larger than the sum of its proper divisors (7294901).

21884691 is an equidigital number, since it uses as much as digits as its factorization.

21884691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7294900.

The product of its digits is 27648, while the sum is 39.

The square root of 21884691 is about 4678.1076302283. The cubic root of 21884691 is about 279.7135292879.

The spelling of 21884691 in words is "twenty-one million, eight hundred eighty-four thousand, six hundred ninety-one".