21172274 has 4 divisors (see below), whose sum is σ = 31758414. Its totient is φ = 10586136.

The previous prime is 21172273. The next prime is 21172309. The reversal of 21172274 is 47227112.

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., 17581249 + 3591025 = 4193^2 + 1895^2 .

It is not an unprimeable number, because it can be changed into a prime (21172273) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5293067 + ... + 5293070.

Almost surely, 2^21172274 is an apocalyptic number.

21172274 is a deficient number, since it is larger than the sum of its proper divisors (10586140).

21172274 is a wasteful number, since it uses less digits than its factorization.

21172274 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10586139.

The product of its digits is 1568, while the sum is 26.

The square root of 21172274 is about 4601.3339370230. Note that the first 3 decimals coincide. The cubic root of 21172274 is about 276.6447939999.

Adding to 21172274 its reverse (47227112), we get a palindrome (68399386).

The spelling of 21172274 in words is "twenty-one million, one hundred seventy-two thousand, two hundred seventy-four".