21312010 has 16 divisors (see below), whose sum is σ = 38743272. Its totient is φ = 8440000.

The previous prime is 21312001. The next prime is 21312017. The reversal of 21312010 is 1021312.

It can be written as a sum of positive squares in 4 ways, for example, as 19298449 + 2013561 = 4393^2 + 1419^2 .

It is a Harshad number since it is a multiple of its sum of digits (10).

It is not an unprimeable number, because it can be changed into a prime (21312017) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9541 + ... + 11560.

Almost surely, 2^21312010 is an apocalyptic number.

21312010 is a deficient number, since it is larger than the sum of its proper divisors (17431262).

21312010 is a wasteful number, since it uses less digits than its factorization.

21312010 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21209.

The product of its (nonzero) digits is 12, while the sum is 10.

The square root of 21312010 is about 4616.4932578744. The cubic root of 21312010 is about 277.2520741011.

Adding to 21312010 its reverse (1021312), we get a palindrome (22333322).

The spelling of 21312010 in words is "twenty-one million, three hundred twelve thousand, ten".