21262664 has 16 divisors (see below), whose sum is σ = 39916800. Its totient is φ = 10618192.

The previous prime is 21262663. The next prime is 21262669. The reversal of 21262664 is 46626212.

It is not an unprimeable number, because it can be changed into a prime (21262663) 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, 10589 + ... + 12435.

It is an arithmetic number, because the mean of its divisors is an integer number (2494800).

Almost surely, 2^21262664 is an apocalyptic number.

It is an amenable number.

21262664 is a deficient number, since it is larger than the sum of its proper divisors (18654136).

21262664 is a wasteful number, since it uses less digits than its factorization.

21262664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3292 (or 3288 counting only the distinct ones).

The product of its digits is 6912, while the sum is 29.

The square root of 21262664 is about 4611.1456277155. The cubic root of 21262664 is about 277.0379248382.

Adding to 21262664 its reverse (46626212), we get a palindrome (67888876).

The spelling of 21262664 in words is "twenty-one million, two hundred sixty-two thousand, six hundred sixty-four".