21422831 has 4 divisors (see below), whose sum is σ = 21456792. Its totient is φ = 21388872.

The previous prime is 21422813. The next prime is 21422833. The reversal of 21422831 is 13822412.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21422831 - 2²² = 17228527 is a prime.

It is a super-2 number, since 2×21422831² = 917875376109122, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21422797 and 21422806.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21422833) 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, 16016 + ... + 17301.

It is an arithmetic number, because the mean of its divisors is an integer number (5364198).

Almost surely, 2^21422831 is an apocalyptic number.

21422831 is a deficient number, since it is larger than the sum of its proper divisors (33961).

21422831 is an equidigital number, since it uses as much as digits as its factorization.

21422831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33960.

The product of its digits is 768, while the sum is 23.

The square root of 21422831 is about 4628.4804201811. The cubic root of 21422831 is about 277.7318074978.

The spelling of 21422831 in words is "twenty-one million, four hundred twenty-two thousand, eight hundred thirty-one".