991091002 has 16 divisors (see below), whose sum is σ = 1636668000. Its totient is φ = 446361840.

The previous prime is 991090967. The next prime is 991091009. The reversal of 991091002 is 200190199.

It is a super-2 number, since 2×991091002² = 1964522748490728008, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (991091009) 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, 204252 + ... + 209047.

It is an arithmetic number, because the mean of its divisors is an integer number (102291750).

Almost surely, 2^991091002 is an apocalyptic number.

991091002 is a deficient number, since it is larger than the sum of its proper divisors (645576998).

991091002 is a wasteful number, since it uses less digits than its factorization.

991091002 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 413421.

The product of its (nonzero) digits is 1458, while the sum is 31.

The square root of 991091002 is about 31481.5978311140. The cubic root of 991091002 is about 997.0214711742.

The spelling of 991091002 in words is "nine hundred ninety-one million, ninety-one thousand, two".