21525274 has 4 divisors (see below), whose sum is σ = 32287914. Its totient is φ = 10762636.

The previous prime is 21525227. The next prime is 21525277. The reversal of 21525274 is 47252512.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 15547249 + 5978025 = 3943^2 + 2445^2 .

It is not an unprimeable number, because it can be changed into a prime (21525277) by changing a digit.

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 as a sum of consecutive naturals, namely, 5381317 + ... + 5381320.

Almost surely, 2^21525274 is an apocalyptic number.

21525274 is a deficient number, since it is larger than the sum of its proper divisors (10762640).

21525274 is a wasteful number, since it uses less digits than its factorization.

21525274 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10762639.

The product of its digits is 5600, while the sum is 28.

The square root of 21525274 is about 4639.5338127877. The cubic root of 21525274 is about 278.1738039845.

Adding to 21525274 its reverse (47252512), we get a palindrome (68777786).

The spelling of 21525274 in words is "twenty-one million, five hundred twenty-five thousand, two hundred seventy-four".