21081310 has 16 divisors (see below), whose sum is σ = 38001600. Its totient is φ = 8420256.

The previous prime is 21081299. The next prime is 21081311. The reversal of 21081310 is 1318012.

It is a super-2 number, since 2×21081310² = 888843262632200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21081311) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 9376 + ... + 11404.

It is an arithmetic number, because the mean of its divisors is an integer number (2375100).

Almost surely, 2^21081310 is an apocalyptic number.

21081310 is a deficient number, since it is larger than the sum of its proper divisors (16920290).

21081310 is a wasteful number, since it uses less digits than its factorization.

21081310 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3075.

The product of its (nonzero) digits is 48, while the sum is 16.

The square root of 21081310 is about 4591.4387723240. The cubic root of 21081310 is about 276.2480354480.

Adding to 21081310 its reverse (1318012), we get a palindrome (22399322).

The spelling of 21081310 in words is "twenty-one million, eighty-one thousand, three hundred ten".