21382869 has 4 divisors (see below), whose sum is σ = 28510496. Its totient is φ = 14255244.

The previous prime is 21382861. The next prime is 21382871. The reversal of 21382869 is 96828312.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21382869 - 2³ = 21382861 is a prime.

It is a super-2 number, since 2×21382869² = 914454173342322, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21382861) 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, 3563809 + ... + 3563814.

It is an arithmetic number, because the mean of its divisors is an integer number (7127624).

Almost surely, 2^21382869 is an apocalyptic number.

It is an amenable number.

21382869 is a deficient number, since it is larger than the sum of its proper divisors (7127627).

21382869 is an equidigital number, since it uses as much as digits as its factorization.

21382869 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7127626.

The product of its digits is 41472, while the sum is 39.

The square root of 21382869 is about 4624.1614374933. The cubic root of 21382869 is about 277.5590070121.

The spelling of 21382869 in words is "twenty-one million, three hundred eighty-two thousand, eight hundred sixty-nine".