21212146 has 8 divisors (see below), whose sum is σ = 31857840. Its totient is φ = 10592868.

The previous prime is 21212143. The next prime is 21212159. The reversal of 21212146 is 64121212.

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 (21212143) 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, 4456 + ... + 7891.

It is an arithmetic number, because the mean of its divisors is an integer number (3982230).

Almost surely, 2^21212146 is an apocalyptic number.

21212146 is a deficient number, since it is larger than the sum of its proper divisors (10645694).

21212146 is a wasteful number, since it uses less digits than its factorization.

21212146 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13208.

The product of its digits is 192, while the sum is 19.

The square root of 21212146 is about 4605.6645557400. The cubic root of 21212146 is about 276.8183458861.

Adding to 21212146 its reverse (64121212), we get a palindrome (85333358).

The spelling of 21212146 in words is "twenty-one million, two hundred twelve thousand, one hundred forty-six".