991004040022 has 4 divisors (see below), whose sum is σ = 1486506060036. Its totient is φ = 495502020010.

The previous prime is 991004039953. The next prime is 991004040073. The reversal of 991004040022 is 220040400199.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 247751010004 + ... + 247751010007.

It is an arithmetic number, because the mean of its divisors is an integer number (371626515009).

Almost surely, 2^991004040022 is an apocalyptic number.

991004040022 is a deficient number, since it is larger than the sum of its proper divisors (495502020014).

991004040022 is a wasteful number, since it uses less digits than its factorization.

991004040022 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 495502020013.

The product of its (nonzero) digits is 5184, while the sum is 31.

The spelling of 991004040022 in words is "nine hundred ninety-one billion, four million, forty thousand, twenty-two".