991664016 has 80 divisors (see below), whose sum is σ = 2955239424. Its totient is φ = 280674432.

The previous prime is 991663993. The next prime is 991664033. The reversal of 991664016 is 610466199.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22161 + ... + 49743.

Almost surely, 2^991664016 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 991664016, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1477619712).

991664016 is an abundant number, since it is smaller than the sum of its proper divisors (1963575408).

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

991664016 is a wasteful number, since it uses less digits than its factorization.

991664016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27708 (or 27702 counting only the distinct ones).

The product of its (nonzero) digits is 69984, while the sum is 42.

The square root of 991664016 is about 31490.6972930102. The cubic root of 991664016 is about 997.2135817514.

The spelling of 991664016 in words is "nine hundred ninety-one million, six hundred sixty-four thousand, sixteen".