145999991 has 2 divisors, whose sum is σ = 145999992. Its totient is φ = 145999990.

The previous prime is 145999981. The next prime is 145999999. The reversal of 145999991 is 199999541.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-145999991 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (145999999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 72999995 + 72999996.

It is an arithmetic number, because the mean of its divisors is an integer number (72999996).

Almost surely, 2^145999991 is an apocalyptic number.

145999991 is a deficient number, since it is larger than the sum of its proper divisors (1).

145999991 is an equidigital number, since it uses as much as digits as its factorization.

145999991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1180980, while the sum is 56.

The square root of 145999991 is about 12083.0456011719. The cubic root of 145999991 is about 526.5637319973.

The spelling of 145999991 in words is "one hundred forty-five million, nine hundred ninety-nine thousand, nine hundred ninety-one".