21211072 has 14 divisors (see below), whose sum is σ = 42090848. Its totient is φ = 10605504.

The previous prime is 21211039. The next prime is 21211079. The reversal of 21211072 is 27011212.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211079) 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, 165648 + ... + 165775.

Almost surely, 2^21211072 is an apocalyptic number.

It is an amenable number.

21211072 is a deficient number, since it is larger than the sum of its proper divisors (20879776).

21211072 is an equidigital number, since it uses as much as digits as its factorization.

21211072 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 331435 (or 331425 counting only the distinct ones).

The product of its (nonzero) digits is 56, while the sum is 16.

The square root of 21211072 is about 4605.5479587124. The cubic root of 21211072 is about 276.8136739099.

Adding to 21211072 its reverse (27011212), we get a palindrome (48222284).

The spelling of 21211072 in words is "twenty-one million, two hundred eleven thousand, seventy-two".