21231188 has 12 divisors (see below), whose sum is σ = 40532352. Its totient is φ = 9650520.

The previous prime is 21231173. The next prime is 21231241. The reversal of 21231188 is 88113212.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 241220 + ... + 241307.

It is an arithmetic number, because the mean of its divisors is an integer number (3377696).

Almost surely, 2^21231188 is an apocalyptic number.

It is an amenable number.

21231188 is a deficient number, since it is larger than the sum of its proper divisors (19301164).

21231188 is a wasteful number, since it uses less digits than its factorization.

21231188 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 482542 (or 482540 counting only the distinct ones).

The product of its digits is 768, while the sum is 26.

The square root of 21231188 is about 4607.7313289731. The cubic root of 21231188 is about 276.9011537646.

The spelling of 21231188 in words is "twenty-one million, two hundred thirty-one thousand, one hundred eighty-eight".