21532369 has 4 divisors (see below), whose sum is σ = 21541744. Its totient is φ = 21522996.

The previous prime is 21532361. The next prime is 21532373. The reversal of 21532369 is 96323512.

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, 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 21532369 - 2³ = 21532361 is a prime.

It is a super-2 number, since 2×21532369² = 927285829504322, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21532369.

It is not an unprimeable number, because it can be changed into a prime (21532361) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1354 + ... + 6700.

It is an arithmetic number, because the mean of its divisors is an integer number (5385436).

Almost surely, 2^21532369 is an apocalyptic number.

It is an amenable number.

21532369 is a deficient number, since it is larger than the sum of its proper divisors (9375).

21532369 is an equidigital number, since it uses as much as digits as its factorization.

21532369 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9374.

The product of its digits is 9720, while the sum is 31.

The square root of 21532369 is about 4640.2983740273. The cubic root of 21532369 is about 278.2043638175.

The spelling of 21532369 in words is "twenty-one million, five hundred thirty-two thousand, three hundred sixty-nine".