991969 has 8 divisors (see below), whose sum is σ = 1117440. Its totient is φ = 872400.

The previous prime is 991961. The next prime is 991973. The reversal of 991969 is 969199.

991969 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 991969 - 2³ = 991961 is a prime.

It is a super-2 number, since 2×991969² = 1968004993922, which contains 22 as substring.

It is a Duffinian number.

991969 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (991961) 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, 1114 + ... + 1795.

It is an arithmetic number, because the mean of its divisors is an integer number (139680).

2⁹⁹¹⁹⁶⁹ is an apocalyptic number.

It is an amenable number.

991969 is a deficient number, since it is larger than the sum of its proper divisors (125471).

991969 is a wasteful number, since it uses less digits than its factorization.

991969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2951.

The product of its digits is 39366, while the sum is 43.

The square root of 991969 is about 995.9764053430. The cubic root of 991969 is about 99.7315801525.

The spelling of 991969 in words is "nine hundred ninety-one thousand, nine hundred sixty-nine".