158181997 has 4 divisors (see below), whose sum is σ = 158276800. Its totient is φ = 158087196.

The previous prime is 158181943. The next prime is 158182027. The reversal of 158181997 is 799181851.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 158181997 - 2⁷ = 158181869 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 158181997.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (158181917) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 44853 + ... + 48250.

It is an arithmetic number, because the mean of its divisors is an integer number (39569200).

Almost surely, 2^158181997 is an apocalyptic number.

It is an amenable number.

158181997 is a deficient number, since it is larger than the sum of its proper divisors (94803).

158181997 is an equidigital number, since it uses as much as digits as its factorization.

158181997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94802.

The product of its digits is 181440, while the sum is 49.

The square root of 158181997 is about 12577.0424583842. The cubic root of 158181997 is about 540.8195112708.

The spelling of 158181997 in words is "one hundred fifty-eight million, one hundred eighty-one thousand, nine hundred ninety-seven".