171998640 has 400 divisors, whose sum is σ = 691384320. Its totient is φ = 39191040.

The previous prime is 171998599. The next prime is 171998663. The reversal of 171998640 is 46899171.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 1354257 + ... + 1354383.

Almost surely, 2^171998640 is an apocalyptic number.

171998640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 171998640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (345692160).

171998640 is an abundant number, since it is smaller than the sum of its proper divisors (519385680).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

171998640 is a wasteful number, since it uses less digits than its factorization.

171998640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 182 (or 167 counting only the distinct ones).

The product of its (nonzero) digits is 108864, while the sum is 45.

The square root of 171998640 is about 13114.8251989876. The cubic root of 171998640 is about 556.1283108799.

The spelling of 171998640 in words is "one hundred seventy-one million, nine hundred ninety-eight thousand, six hundred forty".