1233151991 has 2 divisors, whose sum is σ = 1233151992. Its totient is φ = 1233151990.

The previous prime is 1233151987. The next prime is 1233152017. The reversal of 1233151991 is 1991513321.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1233151991 - 2² = 1233151987 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1233151981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 616575995 + 616575996.

It is an arithmetic number, because the mean of its divisors is an integer number (616575996).

Almost surely, 2^1233151991 is an apocalyptic number.

1233151991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1233151991 is an equidigital number, since it uses as much as digits as its factorization.

1233151991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7290, while the sum is 35.

The square root of 1233151991 is about 35116.2639100460. The cubic root of 1233151991 is about 1072.3557121201.

The spelling of 1233151991 in words is "one billion, two hundred thirty-three million, one hundred fifty-one thousand, nine hundred ninety-one".