21745274 has 8 divisors (see below), whose sum is σ = 32641428. Its totient is φ = 10864800.

The previous prime is 21745247. The next prime is 21745279. The reversal of 21745274 is 47254712.

It can be written as a sum of positive squares in 2 ways, for example, as 18879025 + 2866249 = 4345^2 + 1693^2 .

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

Its product of digits (15680) is a multiple of the sum of its prime divisors (7840).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21745274.

It is not an unprimeable number, because it can be changed into a prime (21745279) 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, 584 + ... + 6620.

Almost surely, 2^21745274 is an apocalyptic number.

21745274 is a deficient number, since it is larger than the sum of its proper divisors (10896154).

21745274 is a wasteful number, since it uses less digits than its factorization.

21745274 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7840.

The product of its digits is 15680, while the sum is 32.

The square root of 21745274 is about 4663.1828186336. The cubic root of 21745274 is about 279.1182893622.

Adding to 21745274 its reverse (47254712), we get a palindrome (68999986).

The spelling of 21745274 in words is "twenty-one million, seven hundred forty-five thousand, two hundred seventy-four".