21642106 has 8 divisors (see below), whose sum is σ = 32534964. Its totient is φ = 10797120.

The previous prime is 21642067. The next prime is 21642107. The reversal of 21642106 is 60124612.

It can be written as a sum of positive squares in 2 ways, for example, as 20331081 + 1311025 = 4509^2 + 1145^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (21642107) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10815 + ... + 12658.

Almost surely, 2^21642106 is an apocalyptic number.

21642106 is a deficient number, since it is larger than the sum of its proper divisors (10892858).

21642106 is a wasteful number, since it uses less digits than its factorization.

21642106 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23936.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 21642106 is about 4652.1076943682. The cubic root of 21642106 is about 278.6761743536.

Adding to 21642106 its reverse (60124612), we get a palindrome (81766718).

The spelling of 21642106 in words is "twenty-one million, six hundred forty-two thousand, one hundred six".