21814591 has 4 divisors (see below), whose sum is σ = 21825000. Its totient is φ = 21804184.

The previous prime is 21814589. The next prime is 21814613. The reversal of 21814591 is 19541812.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21814591 - 2¹ = 21814589 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 (21814291) 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, 841 + ... + 6658.

It is an arithmetic number, because the mean of its divisors is an integer number (5456250).

Almost surely, 2^21814591 is an apocalyptic number.

21814591 is a deficient number, since it is larger than the sum of its proper divisors (10409).

21814591 is an equidigital number, since it uses as much as digits as its factorization.

21814591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10408.

The product of its digits is 2880, while the sum is 31.

The square root of 21814591 is about 4670.6092750304. The cubic root of 21814591 is about 279.4145548213.

The spelling of 21814591 in words is "twenty-one million, eight hundred fourteen thousand, five hundred ninety-one".