21380263 has 8 divisors (see below), whose sum is σ = 22633520. Its totient is φ = 20139840.

The previous prime is 21380257. The next prime is 21380267. The reversal of 21380263 is 36208312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21380263 - 2¹⁷ = 21249191 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 (21380267) 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 7 ways as a sum of consecutive naturals, for example, 331 + ... + 6547.

It is an arithmetic number, because the mean of its divisors is an integer number (2829190).

Almost surely, 2^21380263 is an apocalyptic number.

21380263 is a deficient number, since it is larger than the sum of its proper divisors (1253257).

21380263 is a wasteful number, since it uses less digits than its factorization.

21380263 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6417.

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 21380263 is about 4623.8796480877. The cubic root of 21380263 is about 277.5477308801.

Adding to 21380263 its reverse (36208312), we get a palindrome (57588575).

The spelling of 21380263 in words is "twenty-one million, three hundred eighty thousand, two hundred sixty-three".