156997180217 has 4 divisors (see below), whose sum is σ = 157013117556. Its totient is φ = 156981242880.

The previous prime is 156997180183. The next prime is 156997180271. The reversal of 156997180217 is 712081799651.

It is a happy number.

156997180217 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 118498423696 + 38498756521 = 344236^2 + 196211^2 .

It is a cyclic number.

It is not a de Polignac number, because 156997180217 - 2³⁴ = 139817311033 is a prime.

It is a super-2 number, since 2×156997180217² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (156997185217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7953884 + ... + 7973597.

It is an arithmetic number, because the mean of its divisors is an integer number (39253279389).

Almost surely, 2^156997180217 is an apocalyptic number.

It is an amenable number.

156997180217 is a deficient number, since it is larger than the sum of its proper divisors (15937339).

156997180217 is an equidigital number, since it uses as much as digits as its factorization.

156997180217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15937338.

The product of its (nonzero) digits is 1905120, while the sum is 56.

The spelling of 156997180217 in words is "one hundred fifty-six billion, nine hundred ninety-seven million, one hundred eighty thousand, two hundred seventeen".