21191722 has 8 divisors (see below), whose sum is σ = 31807296. Its totient is φ = 10589292.

The previous prime is 21191699. The next prime is 21191743. The reversal of 21191722 is 22719112.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3823 + ... + 7549.

It is an arithmetic number, because the mean of its divisors is an integer number (3975912).

Almost surely, 2^21191722 is an apocalyptic number.

21191722 is a deficient number, since it is larger than the sum of its proper divisors (10615574).

21191722 is a wasteful number, since it uses less digits than its factorization.

21191722 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6572.

The product of its digits is 504, while the sum is 25.

The square root of 21191722 is about 4603.4467521630. The cubic root of 21191722 is about 276.7294730075.

The spelling of 21191722 in words is "twenty-one million, one hundred ninety-one thousand, seven hundred twenty-two".