171990637 has 12 divisors (see below), whose sum is σ = 215461596. Its totient is φ = 136080000.

The previous prime is 171990629. The next prime is 171990667. The reversal of 171990637 is 736099171.

It can be written as a sum of positive squares in 2 ways, for example, as 53202436 + 118788201 = 7294^2 + 10899^2 .

It is not a de Polignac number, because 171990637 - 2³ = 171990629 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 171990593 and 171990602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (171990607) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 134364 + ... + 135637.

It is an arithmetic number, because the mean of its divisors is an integer number (17955133).

Almost surely, 2^171990637 is an apocalyptic number.

It is an amenable number.

171990637 is a deficient number, since it is larger than the sum of its proper divisors (43470959).

171990637 is a wasteful number, since it uses less digits than its factorization.

171990637 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 270028 (or 270021 counting only the distinct ones).

The product of its (nonzero) digits is 71442, while the sum is 43.

The square root of 171990637 is about 13114.5200827175. The cubic root of 171990637 is about 556.1196853002.

The spelling of 171990637 in words is "one hundred seventy-one million, nine hundred ninety thousand, six hundred thirty-seven".