21791938 has 8 divisors (see below), whose sum is σ = 37357632. Its totient is φ = 9339396.

The previous prime is 21791921. The next prime is 21791969. The reversal of 21791938 is 83919712.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21791938.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 778270 + ... + 778297.

It is an arithmetic number, because the mean of its divisors is an integer number (4669704).

Almost surely, 2^21791938 is an apocalyptic number.

21791938 is a deficient number, since it is larger than the sum of its proper divisors (15565694).

21791938 is a wasteful number, since it uses less digits than its factorization.

21791938 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1556576.

The product of its digits is 27216, while the sum is 40.

The square root of 21791938 is about 4668.1835867926. The cubic root of 21791938 is about 279.3178035212.

The spelling of 21791938 in words is "twenty-one million, seven hundred ninety-one thousand, nine hundred thirty-eight".