21387383 has 8 divisors (see below), whose sum is σ = 21978000. Its totient is φ = 20812344.

The previous prime is 21387361. The next prime is 21387389. The reversal of 21387383 is 38378312.

It is not a de Polignac number, because 21387383 - 2⁶ = 21387319 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 (21387389) 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, 79373 + ... + 79641.

It is an arithmetic number, because the mean of its divisors is an integer number (2747250).

Almost surely, 2^21387383 is an apocalyptic number.

21387383 is a deficient number, since it is larger than the sum of its proper divisors (590617).

21387383 is an frugal number, since it uses more digits than its factorization.

21387383 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 398 (or 312 counting only the distinct ones).

The product of its digits is 24192, while the sum is 35.

The square root of 21387383 is about 4624.6495002324. The cubic root of 21387383 is about 277.5785368704.

The spelling of 21387383 in words is "twenty-one million, three hundred eighty-seven thousand, three hundred eighty-three".