991029312 has 504 divisors, whose sum is σ = 3704804376. Its totient is φ = 250822656.

The previous prime is 991029311. The next prime is 991029337. The reversal of 991029312 is 213920199.

991029312 = T₁₄₈ + T₁₄₉ + ... + T₁₈₁₁.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 194435136 + 796594176 = 13944^2 + 28224^2 .

It is a tau number, because it is divible by the number of its divisors (504).

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (991029311) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 13575708 + ... + 13575780.

Almost surely, 2^991029312 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 991029312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1852402188).

991029312 is an abundant number, since it is smaller than the sum of its proper divisors (2713775064).

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

991029312 is a wasteful number, since it uses less digits than its factorization.

991029312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 155 (or 135 counting only the distinct ones).

The product of its (nonzero) digits is 8748, while the sum is 36.

The square root of 991029312 is about 31480.6180371352. The cubic root of 991029312 is about 997.0007843652. Note that the first 3 decimals are identical.

The spelling of 991029312 in words is "nine hundred ninety-one million, twenty-nine thousand, three hundred twelve".