172998991 has 8 divisors (see below), whose sum is σ = 190491264. Its totient is φ = 155800920.

The previous prime is 172998937. The next prime is 172998997. The reversal of 172998991 is 199899271.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 172998991 - 2⁷ = 172998863 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (172998997) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 72315 + ... + 74668.

It is an arithmetic number, because the mean of its divisors is an integer number (23811408).

Almost surely, 2^172998991 is an apocalyptic number.

172998991 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

172998991 is a deficient number, since it is larger than the sum of its proper divisors (17492273).

172998991 is a wasteful number, since it uses less digits than its factorization.

172998991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 147101.

The product of its digits is 734832, while the sum is 55.

The square root of 172998991 is about 13152.9080814853. The cubic root of 172998991 is about 557.2043822760.

The spelling of 172998991 in words is "one hundred seventy-two million, nine hundred ninety-eight thousand, nine hundred ninety-one".