21102012 has 24 divisors (see below), whose sum is σ = 54709200. Its totient is φ = 7033968.

The previous prime is 21101963. The next prime is 21102023. The reversal of 21102012 is 21020112.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 21101985 and 21102003.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 97587 + ... + 97802.

It is an arithmetic number, because the mean of its divisors is an integer number (2279550).

Almost surely, 2^21102012 is an apocalyptic number.

It is an amenable number.

21102012 is an abundant number, since it is smaller than the sum of its proper divisors (33607188).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21102012 is a wasteful number, since it uses less digits than its factorization.

21102012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195402 (or 195394 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 21102012 is about 4593.6926322949. The cubic root of 21102012 is about 276.3384317257.

Adding to 21102012 its reverse (21020112), we get a palindrome (42122124).

The spelling of 21102012 in words is "twenty-one million, one hundred two thousand, twelve".