171991954 has 4 divisors (see below), whose sum is σ = 257987934. Its totient is φ = 85995976.

The previous prime is 171991949. The next prime is 171991957. The reversal of 171991954 is 459199171.

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

It can be written as a sum of positive squares in only one way, i.e., 125955729 + 46036225 = 11223^2 + 6785^2 .

It is not an unprimeable number, because it can be changed into a prime (171991957) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42997987 + ... + 42997990.

Almost surely, 2^171991954 is an apocalyptic number.

171991954 is a deficient number, since it is larger than the sum of its proper divisors (85995980).

171991954 is an equidigital number, since it uses as much as digits as its factorization.

171991954 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85995979.

The product of its digits is 102060, while the sum is 46.

The square root of 171991954 is about 13114.5702941423. The cubic root of 171991954 is about 556.1211047724.

The spelling of 171991954 in words is "one hundred seventy-one million, nine hundred ninety-one thousand, nine hundred fifty-four".