172691993 has 8 divisors (see below), whose sum is σ = 174213960. Its totient is φ = 171175680.

The previous prime is 172691957. The next prime is 172692017. The reversal of 172691993 is 399196271.

It can be written as a sum of positive squares in 4 ways, for example, as 42549529 + 130142464 = 6523^2 + 11408^2 .

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 172691993 - 2¹² = 172687897 is a prime.

It is a super-3 number, since 3×172691993³ (a number of 26 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (172691293) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 78833 + ... + 80993.

It is an arithmetic number, because the mean of its divisors is an integer number (21776745).

Almost surely, 2^172691993 is an apocalyptic number.

It is an amenable number.

172691993 is a deficient number, since it is larger than the sum of its proper divisors (1521967).

172691993 is a wasteful number, since it uses less digits than its factorization.

172691993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2827.

The product of its digits is 183708, while the sum is 47.

The square root of 172691993 is about 13141.2325525424. The cubic root of 172691993 is about 556.8745886051.

The spelling of 172691993 in words is "one hundred seventy-two million, six hundred ninety-one thousand, nine hundred ninety-three".