1191399990 has 32 divisors (see below), whose sum is σ = 3119302656. Its totient is φ = 288824160.

The previous prime is 1191399983. The next prime is 1191400003. The reversal of 1191399990 is 999931911.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1804822 + ... + 1805481.

It is an arithmetic number, because the mean of its divisors is an integer number (97478208).

Almost surely, 2^1191399990 is an apocalyptic number.

1191399990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1191399990 is an abundant number, since it is smaller than the sum of its proper divisors (1927902666).

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

1191399990 is a wasteful number, since it uses less digits than its factorization.

1191399990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3610324.

The product of its (nonzero) digits is 177147, while the sum is 51.

The square root of 1191399990 is about 34516.6624979878. The cubic root of 1191399990 is about 1060.1139043374.

The spelling of 1191399990 in words is "one billion, one hundred ninety-one million, three hundred ninety-nine thousand, nine hundred ninety".