21006996 has 12 divisors (see below), whose sum is σ = 49016352. Its totient is φ = 7002328.

The previous prime is 21006977. The next prime is 21007001. The reversal of 21006996 is 69960012.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent 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, 875280 + ... + 875303.

It is an arithmetic number, because the mean of its divisors is an integer number (4084696).

Almost surely, 2^21006996 is an apocalyptic number.

It is an amenable number.

21006996 is an abundant number, since it is smaller than the sum of its proper divisors (28009356).

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

21006996 is a wasteful number, since it uses less digits than its factorization.

21006996 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1750590 (or 1750588 counting only the distinct ones).

The product of its (nonzero) digits is 5832, while the sum is 33.

The square root of 21006996 is about 4583.3389575723. The cubic root of 21006996 is about 275.9230514326.

The spelling of 21006996 in words is "twenty-one million, six thousand, nine hundred ninety-six".