21749426 has 8 divisors (see below), whose sum is σ = 34543260. Its totient is φ = 10235008.

The previous prime is 21749423. The next prime is 21749447. The reversal of 21749426 is 62494712.

It can be written as a sum of positive squares in 2 ways, for example, as 21390625 + 358801 = 4625^2 + 599^2 .

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

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21749423) 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, 319811 + ... + 319878.

Almost surely, 2^21749426 is an apocalyptic number.

21749426 is a deficient number, since it is larger than the sum of its proper divisors (12793834).

21749426 is a wasteful number, since it uses less digits than its factorization.

21749426 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 639708.

The product of its digits is 24192, while the sum is 35.

The square root of 21749426 is about 4663.6279868789. The cubic root of 21749426 is about 279.1360529980.

The spelling of 21749426 in words is "twenty-one million, seven hundred forty-nine thousand, four hundred twenty-six".