21339361 has 4 divisors (see below), whose sum is σ = 21350592. Its totient is φ = 21328132.

The previous prime is 21339349. The next prime is 21339371. The reversal of 21339361 is 16393312.

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 21339361 - 2¹⁹ = 20815073 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21339371) 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, 1981 + ... + 6826.

It is an arithmetic number, because the mean of its divisors is an integer number (5337648).

Almost surely, 2^21339361 is an apocalyptic number.

It is an amenable number.

21339361 is a deficient number, since it is larger than the sum of its proper divisors (11231).

21339361 is an equidigital number, since it uses as much as digits as its factorization.

21339361 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11230.

The product of its digits is 2916, while the sum is 28.

The square root of 21339361 is about 4619.4546214894. The cubic root of 21339361 is about 277.3706282220.

The spelling of 21339361 in words is "twenty-one million, three hundred thirty-nine thousand, three hundred sixty-one".