21090274 has 4 divisors (see below), whose sum is σ = 31635414. Its totient is φ = 10545136.

The previous prime is 21090271. The next prime is 21090299. The reversal of 21090274 is 47209012.

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., 12299049 + 8791225 = 3507^2 + 2965^2 .

It is not an unprimeable number, because it can be changed into a prime (21090271) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5272567 + ... + 5272570.

Almost surely, 2^21090274 is an apocalyptic number.

21090274 is a deficient number, since it is larger than the sum of its proper divisors (10545140).

21090274 is a wasteful number, since it uses less digits than its factorization.

21090274 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10545139.

The product of its (nonzero) digits is 1008, while the sum is 25.

The square root of 21090274 is about 4592.4148331787. The cubic root of 21090274 is about 276.2871844461.

Adding to 21090274 its reverse (47209012), we get a palindrome (68299286).

The spelling of 21090274 in words is "twenty-one million, ninety thousand, two hundred seventy-four".