172991923 has 8 divisors (see below), whose sum is σ = 189080528. Its totient is φ = 157300704.

The previous prime is 172991921. The next prime is 172991963. The reversal of 172991923 is 329199271.

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

It is a cyclic number.

It is not a de Polignac number, because 172991923 - 2¹ = 172991921 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 172991923.

It is not an unprimeable number, because it can be changed into a prime (172991921) 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, 98436 + ... + 100177.

It is an arithmetic number, because the mean of its divisors is an integer number (23635066).

Almost surely, 2^172991923 is an apocalyptic number.

172991923 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

172991923 is a deficient number, since it is larger than the sum of its proper divisors (16088605).

172991923 is a wasteful number, since it uses less digits than its factorization.

172991923 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 198693.

The product of its digits is 61236, while the sum is 43.

The square root of 172991923 is about 13152.6393929127. The cubic root of 172991923 is about 557.1967938421.

The spelling of 172991923 in words is "one hundred seventy-two million, nine hundred ninety-one thousand, nine hundred twenty-three".