21271642 has 32 divisors (see below), whose sum is σ = 39297024. Its totient is φ = 8434800.

The previous prime is 21271637. The next prime is 21271643. The reversal of 21271642 is 24617212.

It is a Smith number, since the sum of its digits (25) 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 (21271643) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8917 + ... + 11047.

It is an arithmetic number, because the mean of its divisors is an integer number (1228032).

Almost surely, 2^21271642 is an apocalyptic number.

21271642 is a deficient number, since it is larger than the sum of its proper divisors (18025382).

21271642 is a wasteful number, since it uses less digits than its factorization.

21271642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2194.

The product of its digits is 1344, while the sum is 25.

The square root of 21271642 is about 4612.1190357579. The cubic root of 21271642 is about 277.0769117449.

Adding to 21271642 its reverse (24617212), we get a palindrome (45888854).

The spelling of 21271642 in words is "twenty-one million, two hundred seventy-one thousand, six hundred forty-two".