21389373 has 16 divisors (see below), whose sum is σ = 32018560. Its totient is φ = 14110848.

The previous prime is 21389363. The next prime is 21389377. The reversal of 21389373 is 37398312.

It is a happy number.

It is not a de Polignac number, because 21389373 - 2¹³ = 21381181 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 (21389377) 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 15 ways as a sum of consecutive naturals, for example, 1465 + ... + 6702.

It is an arithmetic number, because the mean of its divisors is an integer number (2001160).

Almost surely, 2^21389373 is an apocalyptic number.

It is an amenable number.

21389373 is a deficient number, since it is larger than the sum of its proper divisors (10629187).

21389373 is an equidigital number, since it uses as much as digits as its factorization.

21389373 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8273 (or 8267 counting only the distinct ones).

The product of its digits is 27216, while the sum is 36.

The square root of 21389373 is about 4624.8646466681. The cubic root of 21389373 is about 277.5871457491.

It can be divided in two parts, 2138 and 9373, that added together give a palindrome (11511).

The spelling of 21389373 in words is "twenty-one million, three hundred eighty-nine thousand, three hundred seventy-three".