21223071 has 12 divisors (see below), whose sum is σ = 31076448. Its totient is φ = 13954464.

The previous prime is 21223061. The next prime is 21223073. The reversal of 21223071 is 17032212.

It is not a de Polignac number, because 21223071 - 2⁹ = 21222559 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21223073) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 15495 + ... + 16808.

It is an arithmetic number, because the mean of its divisors is an integer number (2589704).

Almost surely, 2^21223071 is an apocalyptic number.

21223071 is a deficient number, since it is larger than the sum of its proper divisors (9853377).

21223071 is a wasteful number, since it uses less digits than its factorization.

21223071 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32382 (or 32379 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 18.

The square root of 21223071 is about 4606.8504425475. The cubic root of 21223071 is about 276.8658614522.

Adding to 21223071 its reverse (17032212), we get a palindrome (38255283).

The spelling of 21223071 in words is "twenty-one million, two hundred twenty-three thousand, seventy-one".