158217519781 has 2 divisors, whose sum is σ = 158217519782. Its totient is φ = 158217519780.

The previous prime is 158217519737. The next prime is 158217519799. The reversal of 158217519781 is 187915712851.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 128403972225 + 29813547556 = 358335^2 + 172666^2 .

It is a cyclic number.

It is not a de Polignac number, because 158217519781 - 2⁹ = 158217519269 is a prime.

It is a super-2 number, since 2×158217519781² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (158217516781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 79108759890 + 79108759891.

It is an arithmetic number, because the mean of its divisors is an integer number (79108759891).

Almost surely, 2^158217519781 is an apocalyptic number.

It is an amenable number.

158217519781 is a deficient number, since it is larger than the sum of its proper divisors (1).

158217519781 is an equidigital number, since it uses as much as digits as its factorization.

158217519781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1411200, while the sum is 55.

The spelling of 158217519781 in words is "one hundred fifty-eight billion, two hundred seventeen million, five hundred nineteen thousand, seven hundred eighty-one".