21103512 has 32 divisors (see below), whose sum is σ = 55054080. Its totient is φ = 6728480.

The previous prime is 21103501. The next prime is 21103513. The reversal of 21103512 is 21530112.

It is a junction number, because it is equal to n+sod(n) for n = 21103491 and 21103500.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21103513) 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, 18564 + ... + 19667.

It is an arithmetic number, because the mean of its divisors is an integer number (1720440).

Almost surely, 2^21103512 is an apocalyptic number.

It is an amenable number.

21103512 is an abundant number, since it is smaller than the sum of its proper divisors (33950568).

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

21103512 is a wasteful number, since it uses less digits than its factorization.

21103512 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38263 (or 38259 counting only the distinct ones).

The product of its (nonzero) digits is 60, while the sum is 15.

The square root of 21103512 is about 4593.8558967386. The cubic root of 21103512 is about 276.3449792502.

Adding to 21103512 its reverse (21530112), we get a palindrome (42633624).

The spelling of 21103512 in words is "twenty-one million, one hundred three thousand, five hundred twelve".