21219012 has 36 divisors (see below), whose sum is σ = 53778816. Its totient is φ = 7054320.

The previous prime is 21219007. The next prime is 21219013. The reversal of 21219012 is 21091212.

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-2 number, since 2×21219012² = 900492940512288, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (21219013) 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 11 ways as a sum of consecutive naturals, for example, 22837 + ... + 23747.

It is an arithmetic number, because the mean of its divisors is an integer number (1493856).

Almost surely, 2^21219012 is an apocalyptic number.

It is an amenable number.

21219012 is an abundant number, since it is smaller than the sum of its proper divisors (32559804).

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

21219012 is a wasteful number, since it uses less digits than its factorization.

21219012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1568 (or 1563 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

The square root of 21219012 is about 4606.4098818928. The cubic root of 21219012 is about 276.8482097470.

The spelling of 21219012 in words is "twenty-one million, two hundred nineteen thousand, twelve".