21830779 has 4 divisors (see below), whose sum is σ = 21888760. Its totient is φ = 21772800.

The previous prime is 21830773. The next prime is 21830797. The reversal of 21830779 is 97703812.

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 21830779 - 2⁹ = 21830267 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21830773) 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, 28422 + ... + 29179.

It is an arithmetic number, because the mean of its divisors is an integer number (5472190).

Almost surely, 2^21830779 is an apocalyptic number.

21830779 is a deficient number, since it is larger than the sum of its proper divisors (57981).

21830779 is an equidigital number, since it uses as much as digits as its factorization.

21830779 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57980.

The product of its (nonzero) digits is 21168, while the sum is 37.

The square root of 21830779 is about 4672.3419181391. The cubic root of 21830779 is about 279.4836529834.

The spelling of 21830779 in words is "twenty-one million, eight hundred thirty thousand, seven hundred seventy-nine".