1151999991 has 12 divisors (see below), whose sum is σ = 1664312832. Its totient is φ = 767855616.

The previous prime is 1151999987. The next prime is 1151999993. The reversal of 1151999991 is 1999991511.

It is not a de Polignac number, because 1151999991 - 2² = 1151999987 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1151999993) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 63370 + ... + 79496.

It is an arithmetic number, because the mean of its divisors is an integer number (138692736).

Almost surely, 2^1151999991 is an apocalyptic number.

1151999991 is a deficient number, since it is larger than the sum of its proper divisors (512312841).

1151999991 is a wasteful number, since it uses less digits than its factorization.

1151999991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24070 (or 24067 counting only the distinct ones).

The product of its digits is 295245, while the sum is 54.

The square root of 1151999991 is about 33941.1253643718. The cubic root of 1151999991 is about 1048.2965549536.

The spelling of 1151999991 in words is "one billion, one hundred fifty-one million, nine hundred ninety-nine thousand, nine hundred ninety-one".