20891616 has 48 divisors (see below), whose sum is σ = 55112400. Its totient is φ = 6929408.

The previous prime is 20891603. The next prime is 20891639. The reversal of 20891616 is 61619802.

It is a tau number, because it is divible by the number of its divisors (48).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25420 + ... + 26228.

It is an arithmetic number, because the mean of its divisors is an integer number (1148175).

Almost surely, 2^20891616 is an apocalyptic number.

It is an amenable number.

20891616 is an abundant number, since it is smaller than the sum of its proper divisors (34220784).

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

20891616 is a wasteful number, since it uses less digits than its factorization.

20891616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1091 (or 1083 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 33.

The square root of 20891616 is about 4570.7347330599. The cubic root of 20891616 is about 275.4169586668.

The spelling of 20891616 in words is "twenty million, eight hundred ninety-one thousand, six hundred sixteen".