21231351 has 24 divisors (see below), whose sum is σ = 32685120. Its totient is φ = 13234176.

The previous prime is 21231313. The next prime is 21231359. The reversal of 21231351 is 15313212.

It is not a de Polignac number, because 21231351 - 2¹¹ = 21229303 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21231359) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 29170 + ... + 29888.

It is an arithmetic number, because the mean of its divisors is an integer number (1361880).

Almost surely, 2^21231351 is an apocalyptic number.

21231351 is a deficient number, since it is larger than the sum of its proper divisors (11453769).

21231351 is a wasteful number, since it uses less digits than its factorization.

21231351 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 935 (or 932 counting only the distinct ones).

The product of its digits is 180, while the sum is 18.

The square root of 21231351 is about 4607.7490166024. The cubic root of 21231351 is about 276.9018623884.

Adding to 21231351 its reverse (15313212), we get a palindrome (36544563).

The spelling of 21231351 in words is "twenty-one million, two hundred thirty-one thousand, three hundred fifty-one".