153991 has 2 divisors, whose sum is σ = 153992. Its totient is φ = 153990.

The previous prime is 153953. The next prime is 153997. The reversal of 153991 is 199351.

153991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 153991 - 2¹³ = 145799 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (153997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 76995 + 76996.

It is an arithmetic number, because the mean of its divisors is an integer number (76996).

2¹⁵³⁹⁹¹ is an apocalyptic number.

153991 is a deficient number, since it is larger than the sum of its proper divisors (1).

153991 is an equidigital number, since it uses as much as digits as its factorization.

153991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1215, while the sum is 28.

The square root of 153991 is about 392.4168701776. The cubic root of 153991 is about 53.6000399123.

It can be divided in two parts, 15399 and 1, that added together give a triangular number (15400 = T₁₇₅).

The spelling of 153991 in words is "one hundred fifty-three thousand, nine hundred ninety-one".