21213123010 has 16 divisors (see below), whose sum is σ = 38221038072. Its totient is φ = 8476934400.

The previous prime is 21213122999. The next prime is 21213123011. The reversal of 21213123010 is 1032131212.

It can be written as a sum of positive squares in 4 ways, for example, as 16312142961 + 4900980049 = 127719^2 + 70007^2 .

It is not an unprimeable number, because it can be changed into a prime (21213123011) 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, 1028631 + ... + 1049050.

Almost surely, 2^21213123010 is an apocalyptic number.

21213123010 is a deficient number, since it is larger than the sum of its proper divisors (17007915062).

21213123010 is a wasteful number, since it uses less digits than its factorization.

21213123010 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2078709.

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

Adding to 21213123010 its reverse (1032131212), we get a palindrome (22245254222).

The spelling of 21213123010 in words is "twenty-one billion, two hundred thirteen million, one hundred twenty-three thousand, ten".