20421274 has 4 divisors (see below), whose sum is σ = 30631914. Its totient is φ = 10210636.

The previous prime is 20421253. The next prime is 20421277. The reversal of 20421274 is 47212402.

It is a happy number.

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., 15327225 + 5094049 = 3915^2 + 2257^2 .

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (20421277) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5105317 + ... + 5105320.

Almost surely, 2^20421274 is an apocalyptic number.

20421274 is a deficient number, since it is larger than the sum of its proper divisors (10210640).

20421274 is a wasteful number, since it uses less digits than its factorization.

20421274 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10210639.

The product of its (nonzero) digits is 896, while the sum is 22.

The square root of 20421274 is about 4518.9903739663. The cubic root of 20421274 is about 273.3343905703.

Adding to 20421274 its reverse (47212402), we get a palindrome (67633676).

The spelling of 20421274 in words is "twenty million, four hundred twenty-one thousand, two hundred seventy-four".