1991016 has 24 divisors (see below), whose sum is σ = 5392530. Its totient is φ = 663648.

The previous prime is 1990987. The next prime is 1991027. The reversal of 1991016 is 6101991.

It can be written as a sum of positive squares in only one way, i.e., 1988100 + 2916 = 1410^2 + 54^2 .

It is a tau number, because it is divible by the number of its divisors (24).

It is an Ulam number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 13755 + ... + 13898.

2^1991016 is an apocalyptic number.

It is an amenable number.

1991016 is an abundant number, since it is smaller than the sum of its proper divisors (3401514).

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

1991016 is a wasteful number, since it uses less digits than its factorization.

1991016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27665 (or 27658 counting only the distinct ones).

The product of its (nonzero) digits is 486, while the sum is 27.

The square root of 1991016 is about 1411.0336636665. The cubic root of 1991016 is about 125.8031696287.

The spelling of 1991016 in words is "one million, nine hundred ninety-one thousand, sixteen".