21379783 has 4 divisors (see below), whose sum is σ = 21834720. Its totient is φ = 20924848.

The previous prime is 21379763. The next prime is 21379817. The reversal of 21379783 is 38797312.

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

It is a cyclic number.

It is not a de Polignac number, because 21379783 - 2⁹ = 21379271 is a prime.

It is a super-2 number, since 2×21379783² = 914190242254178, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21379703) 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, 227398 + ... + 227491.

It is an arithmetic number, because the mean of its divisors is an integer number (5458680).

Almost surely, 2^21379783 is an apocalyptic number.

21379783 is a deficient number, since it is larger than the sum of its proper divisors (454937).

21379783 is an equidigital number, since it uses as much as digits as its factorization.

21379783 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 454936.

The product of its digits is 63504, while the sum is 40.

The square root of 21379783 is about 4623.8277433313. The cubic root of 21379783 is about 277.5456538257.

The spelling of 21379783 in words is "twenty-one million, three hundred seventy-nine thousand, seven hundred eighty-three".