21347889 has 4 divisors (see below), whose sum is σ = 28463856. Its totient is φ = 14231924.

The previous prime is 21347873. The next prime is 21347897. The reversal of 21347889 is 98874312.

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 21347889 - 2⁴ = 21347873 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21347889.

It is not an unprimeable number, because it can be changed into a prime (21347819) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3557979 + ... + 3557984.

It is an arithmetic number, because the mean of its divisors is an integer number (7115964).

Almost surely, 2^21347889 is an apocalyptic number.

It is an amenable number.

21347889 is a deficient number, since it is larger than the sum of its proper divisors (7115967).

21347889 is an equidigital number, since it uses as much as digits as its factorization.

21347889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7115966.

The product of its digits is 96768, while the sum is 42.

The square root of 21347889 is about 4620.3775819731. The cubic root of 21347889 is about 277.4075724974.

The spelling of 21347889 in words is "twenty-one million, three hundred forty-seven thousand, eight hundred eighty-nine".