21271402 has 4 divisors (see below), whose sum is σ = 31907106. Its totient is φ = 10635700.

The previous prime is 21271381. The next prime is 21271409. The reversal of 21271402 is 20417212.

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., 20875761 + 395641 = 4569^2 + 629^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21271402.

It is not an unprimeable number, because it can be changed into a prime (21271409) 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, 5317849 + ... + 5317852.

Almost surely, 2^21271402 is an apocalyptic number.

21271402 is a deficient number, since it is larger than the sum of its proper divisors (10635704).

21271402 is a wasteful number, since it uses less digits than its factorization.

21271402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10635703.

The product of its (nonzero) digits is 224, while the sum is 19.

The square root of 21271402 is about 4612.0930172753. The cubic root of 21271402 is about 277.0758696892.

Adding to 21271402 its reverse (20417212), we get a palindrome (41688614).

The spelling of 21271402 in words is "twenty-one million, two hundred seventy-one thousand, four hundred two".