21188012 has 12 divisors (see below), whose sum is σ = 37274496. Its totient is φ = 10538160.

The previous prime is 21188003. The next prime is 21188029. The reversal of 21188012 is 21088112.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13103 + ... + 14630.

It is an arithmetic number, because the mean of its divisors is an integer number (3106208).

Almost surely, 2^21188012 is an apocalyptic number.

It is an amenable number.

21188012 is a deficient number, since it is larger than the sum of its proper divisors (16086484).

21188012 is a wasteful number, since it uses less digits than its factorization.

21188012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27928 (or 27926 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 23.

The square root of 21188012 is about 4603.0437755902. The cubic root of 21188012 is about 276.7133232068.

The spelling of 21188012 in words is "twenty-one million, one hundred eighty-eight thousand, twelve".