1001992991 has 6 divisors (see below), whose sum is σ = 1007848440. Its totient is φ = 996171368.

The previous prime is 1001992969. The next prime is 1001993011. The reversal of 1001992991 is 1992991001.

It is a happy number.

It is not a de Polignac number, because 1001992991 - 2²⁶ = 934884127 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1001992951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 13190 + ... + 46668.

It is an arithmetic number, because the mean of its divisors is an integer number (167974740).

Almost surely, 2^1001992991 is an apocalyptic number.

1001992991 is a deficient number, since it is larger than the sum of its proper divisors (5855449).

1001992991 is an frugal number, since it uses more digits than its factorization.

1001992991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33825 (or 33652 counting only the distinct ones).

The product of its (nonzero) digits is 13122, while the sum is 41.

The square root of 1001992991 is about 31654.2728711307. The cubic root of 1001992991 is about 1000.6638894865.

The spelling of 1001992991 in words is "one billion, one million, nine hundred ninety-two thousand, nine hundred ninety-one".