991630 has 16 divisors (see below), whose sum is σ = 1819584. Its totient is φ = 388960.

The previous prime is 991621. The next prime is 991633. The reversal of 991630 is 36199.

It is a happy number.

991630 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991633) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 406 + ... + 1465.

It is an arithmetic number, because the mean of its divisors is an integer number (113724).

2⁹⁹¹⁶³⁰ is an apocalyptic number.

991630 is a deficient number, since it is larger than the sum of its proper divisors (827954).

991630 is a wasteful number, since it uses less digits than its factorization.

991630 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1931.

The product of its (nonzero) digits is 1458, while the sum is 28.

The square root of 991630 is about 995.8062060461. The cubic root of 991630 is about 99.7202179501.

The spelling of 991630 in words is "nine hundred ninety-one thousand, six hundred thirty".