21031310 has 16 divisors (see below), whose sum is σ = 37915776. Its totient is φ = 8399328.

The previous prime is 21031303. The next prime is 21031313. The reversal of 21031310 is 1313012.

It is a super-2 number, since 2×21031310² = 884632000632200, which contains 22 as substring.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21031291 and 21031300.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21031313) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7412 + ... + 9848.

It is an arithmetic number, because the mean of its divisors is an integer number (2369736).

Almost surely, 2^21031310 is an apocalyptic number.

21031310 is a deficient number, since it is larger than the sum of its proper divisors (16884466).

21031310 is a wasteful number, since it uses less digits than its factorization.

21031310 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3307.

The product of its (nonzero) digits is 18, while the sum is 11.

The square root of 21031310 is about 4585.9906236276. The cubic root of 21031310 is about 276.0294637033.

Adding to 21031310 its reverse (1313012), we get a palindrome (22344322).

The spelling of 21031310 in words is "twenty-one million, thirty-one thousand, three hundred ten".