21993016 has 8 divisors (see below), whose sum is σ = 41236920. Its totient is φ = 10996504.

The previous prime is 21993007. The next prime is 21993067. The reversal of 21993016 is 61039912.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1374556 + ... + 1374571.

It is an arithmetic number, because the mean of its divisors is an integer number (5154615).

Almost surely, 2^21993016 is an apocalyptic number.

It is an amenable number.

21993016 is a deficient number, since it is larger than the sum of its proper divisors (19243904).

21993016 is a wasteful number, since it uses less digits than its factorization.

21993016 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2749133 (or 2749129 counting only the distinct ones).

The product of its (nonzero) digits is 2916, while the sum is 31.

The square root of 21993016 is about 4689.6712038266. The cubic root of 21993016 is about 280.1742792567.

The spelling of 21993016 in words is "twenty-one million, nine hundred ninety-three thousand, sixteen".