16721916 has 12 divisors (see below), whose sum is σ = 39017832. Its totient is φ = 5573968.

The previous prime is 16721911. The next prime is 16721917. The reversal of 16721916 is 61912761.

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

It is a super-2 number, since 2×16721916² = 559244949422112, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16721911) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 696735 + ... + 696758.

It is an arithmetic number, because the mean of its divisors is an integer number (3251486).

Almost surely, 2^16721916 is an apocalyptic number.

It is an amenable number.

16721916 is an abundant number, since it is smaller than the sum of its proper divisors (22295916).

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

16721916 is a wasteful number, since it uses less digits than its factorization.

16721916 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1393500 (or 1393498 counting only the distinct ones).

The product of its digits is 4536, while the sum is 33.

The square root of 16721916 is about 4089.2439398989. The cubic root of 16721916 is about 255.7184200526.

The spelling of 16721916 in words is "sixteen million, seven hundred twenty-one thousand, nine hundred sixteen".