21384337 has 4 divisors (see below), whose sum is σ = 23029300. Its totient is φ = 19739376.

The previous prime is 21384313. The next prime is 21384347. The reversal of 21384337 is 73348312.

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 1679616 + 19704721 = 1296^2 + 4439^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21384337 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21384299 and 21384308.

It is not an unprimeable number, because it can be changed into a prime (21384347) 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, 822462 + ... + 822487.

It is an arithmetic number, because the mean of its divisors is an integer number (5757325).

Almost surely, 2^21384337 is an apocalyptic number.

It is an amenable number.

21384337 is a deficient number, since it is larger than the sum of its proper divisors (1644963).

21384337 is a wasteful number, since it uses less digits than its factorization.

21384337 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1644962.

The product of its digits is 12096, while the sum is 31.

The square root of 21384337 is about 4624.3201662515. The cubic root of 21384337 is about 277.5653586278.

The spelling of 21384337 in words is "twenty-one million, three hundred eighty-four thousand, three hundred thirty-seven".