21087349 has 4 divisors (see below), whose sum is σ = 21536064. Its totient is φ = 20638636.

The previous prime is 21087337. The next prime is 21087377. The reversal of 21087349 is 94378012.

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 a cyclic number.

It is not a de Polignac number, because 21087349 - 2⁷ = 21087221 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 (21087049) 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, 224287 + ... + 224380.

It is an arithmetic number, because the mean of its divisors is an integer number (5384016).

Almost surely, 2^21087349 is an apocalyptic number.

It is an amenable number.

21087349 is a deficient number, since it is larger than the sum of its proper divisors (448715).

21087349 is an equidigital number, since it uses as much as digits as its factorization.

21087349 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 448714.

The product of its (nonzero) digits is 12096, while the sum is 34.

The square root of 21087349 is about 4592.0963622293. The cubic root of 21087349 is about 276.2744111431.

The spelling of 21087349 in words is "twenty-one million, eighty-seven thousand, three hundred forty-nine".