21845783 has 4 divisors (see below), whose sum is σ = 21923808. Its totient is φ = 21767760.

The previous prime is 21845779. The next prime is 21845807. The reversal of 21845783 is 38754812.

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 21845783 - 2² = 21845779 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 (21845723) 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, 38591 + ... + 39152.

It is an arithmetic number, because the mean of its divisors is an integer number (5480952).

Almost surely, 2^21845783 is an apocalyptic number.

21845783 is a deficient number, since it is larger than the sum of its proper divisors (78025).

21845783 is an equidigital number, since it uses as much as digits as its factorization.

21845783 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78024.

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

The square root of 21845783 is about 4673.9472611488. The cubic root of 21845783 is about 279.5476667689.

The spelling of 21845783 in words is "twenty-one million, eight hundred forty-five thousand, seven hundred eighty-three".