21319912 has 8 divisors (see below), whose sum is σ = 39974850. Its totient is φ = 10659952.

The previous prime is 21319889. The next prime is 21319937. The reversal of 21319912 is 21991312.

It can be written as a sum of positive squares in only one way, i.e., 18610596 + 2709316 = 4314^2 + 1646^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1332487 + ... + 1332502.

Almost surely, 2^21319912 is an apocalyptic number.

It is an amenable number.

21319912 is a deficient number, since it is larger than the sum of its proper divisors (18654938).

21319912 is a wasteful number, since it uses less digits than its factorization.

21319912 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2664995 (or 2664991 counting only the distinct ones).

The product of its digits is 972, while the sum is 28.

The square root of 21319912 is about 4617.3490229784. The cubic root of 21319912 is about 277.2863360842.

The spelling of 21319912 in words is "twenty-one million, three hundred nineteen thousand, nine hundred twelve".