21361349 has 4 divisors (see below), whose sum is σ = 21454860. Its totient is φ = 21267840.

The previous prime is 21361303. The next prime is 21361391. The reversal of 21361349 is 94316312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 20638849 + 722500 = 4543^2 + 850^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21361349 is a prime.

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 (21061349) 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, 46412 + ... + 46869.

It is an arithmetic number, because the mean of its divisors is an integer number (5363715).

Almost surely, 2^21361349 is an apocalyptic number.

It is an amenable number.

21361349 is a deficient number, since it is larger than the sum of its proper divisors (93511).

21361349 is an equidigital number, since it uses as much as digits as its factorization.

21361349 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 93510.

The product of its digits is 3888, while the sum is 29.

The square root of 21361349 is about 4621.8339433606. The cubic root of 21361349 is about 277.4658627487.

The spelling of 21361349 in words is "twenty-one million, three hundred sixty-one thousand, three hundred forty-nine".