21458783 has 4 divisors (see below), whose sum is σ = 21470568. Its totient is φ = 21447000.

The previous prime is 21458741. The next prime is 21458797. The reversal of 21458783 is 38785412.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21458783 - 2⁶ = 21458719 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21458383) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2516 + ... + 7017.

It is an arithmetic number, because the mean of its divisors is an integer number (5367642).

Almost surely, 2^21458783 is an apocalyptic number.

21458783 is a deficient number, since it is larger than the sum of its proper divisors (11785).

21458783 is an equidigital number, since it uses as much as digits as its factorization.

21458783 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11784.

The product of its digits is 53760, while the sum is 38.

The square root of 21458783 is about 4632.3625721655. The cubic root of 21458783 is about 277.8870847267.

The spelling of 21458783 in words is "twenty-one million, four hundred fifty-eight thousand, seven hundred eighty-three".