991288 has 8 divisors (see below), whose sum is σ = 1858680. Its totient is φ = 495640.

The previous prime is 991273. The next prime is 991313. The reversal of 991288 is 882199.

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

It is a plaindrome in base 15.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61948 + ... + 61963.

It is an arithmetic number, because the mean of its divisors is an integer number (232335).

2⁹⁹¹²⁸⁸ is an apocalyptic number.

It is an amenable number.

991288 is a deficient number, since it is larger than the sum of its proper divisors (867392).

991288 is a wasteful number, since it uses less digits than its factorization.

991288 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123917 (or 123913 counting only the distinct ones).

The product of its digits is 10368, while the sum is 37.

The square root of 991288 is about 995.6344710786. The cubic root of 991288 is about 99.7087525729.

It can be divided in two parts, 9912 and 88, that added together give a 4-th power (10000 = 10⁴).

The spelling of 991288 in words is "nine hundred ninety-one thousand, two hundred eighty-eight".