991026972 has 144 divisors (see below), whose sum is σ = 2821797888. Its totient is φ = 291185280.

The previous prime is 991026899. The next prime is 991026979. The reversal of 991026972 is 279620199.

It is a Cunningham number, because it is equal to 997³-1.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991026979) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1203753 + ... + 1204575.

Almost surely, 2^991026972 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 991026972, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1410898944).

991026972 is an abundant number, since it is smaller than the sum of its proper divisors (1830770916).

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

991026972 is a wasteful number, since it uses less digits than its factorization.

991026972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 960 (or 955 counting only the distinct ones).

The product of its (nonzero) digits is 122472, while the sum is 45.

The square root of 991026972 is about 31480.5808713880. The cubic root of 991026972 is about 996.9999996647. Note that the first 6 decimals are identical.

The spelling of 991026972 in words is "nine hundred ninety-one million, twenty-six thousand, nine hundred seventy-two".