133251991 has 2 divisors, whose sum is σ = 133251992. Its totient is φ = 133251990.

The previous prime is 133251983. The next prime is 133252037. The reversal of 133251991 is 199152331.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 133251991 - 2³ = 133251983 is a prime.

It is a nialpdrome in base 15.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (133251931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 66625995 + 66625996.

It is an arithmetic number, because the mean of its divisors is an integer number (66625996).

Almost surely, 2^133251991 is an apocalyptic number.

133251991 is a deficient number, since it is larger than the sum of its proper divisors (1).

133251991 is an equidigital number, since it uses as much as digits as its factorization.

133251991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7290, while the sum is 34.

The square root of 133251991 is about 11543.4826200761. The cubic root of 133251991 is about 510.7690448000.

The spelling of 133251991 in words is "one hundred thirty-three million, two hundred fifty-one thousand, nine hundred ninety-one".