21231610 has 8 divisors (see below), whose sum is σ = 38216916. Its totient is φ = 8492640.

The previous prime is 21231601. The next prime is 21231611. The reversal of 21231610 is 1613212.

It can be written as a sum of positive squares in 2 ways, for example, as 20493729 + 737881 = 4527^2 + 859^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (21231611) 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 3 ways as a sum of consecutive naturals, for example, 1061571 + ... + 1061590.

Almost surely, 2^21231610 is an apocalyptic number.

21231610 is a deficient number, since it is larger than the sum of its proper divisors (16985306).

21231610 is a wasteful number, since it uses less digits than its factorization.

21231610 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2123168.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 21231610 is about 4607.7771213460. Note that the first 3 decimals coincide. The cubic root of 21231610 is about 276.9029883536.

Adding to 21231610 its reverse (1613212), we get a palindrome (22844822).

The spelling of 21231610 in words is "twenty-one million, two hundred thirty-one thousand, six hundred ten".