991624 has 8 divisors (see below), whose sum is σ = 1859310. Its totient is φ = 495808.

The previous prime is 991621. The next prime is 991633. The reversal of 991624 is 426199.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 515524 + 476100 = 718^2 + 690^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61969 + ... + 61984.

2⁹⁹¹⁶²⁴ is an apocalyptic number.

It is an amenable number.

991624 is a deficient number, since it is larger than the sum of its proper divisors (867686).

991624 is a wasteful number, since it uses less digits than its factorization.

991624 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123959 (or 123955 counting only the distinct ones).

The product of its digits is 3888, while the sum is 31.

The square root of 991624 is about 995.8031934072. The cubic root of 991624 is about 99.7200168258.

The spelling of 991624 in words is "nine hundred ninety-one thousand, six hundred twenty-four".