172991549 has 8 divisors (see below), whose sum is σ = 174877560. Its totient is φ = 171115776.

The previous prime is 172991543. The next prime is 172991569. The reversal of 172991549 is 945199271.

It can be written as a sum of positive squares in 4 ways, for example, as 6400900 + 166590649 = 2530^2 + 12907^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-172991549 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 (172991543) 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, 34217 + ... + 38945.

It is an arithmetic number, because the mean of its divisors is an integer number (21859695).

Almost surely, 2^172991549 is an apocalyptic number.

It is an amenable number.

172991549 is a deficient number, since it is larger than the sum of its proper divisors (1886011).

172991549 is a wasteful number, since it uses less digits than its factorization.

172991549 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5119.

The product of its digits is 204120, while the sum is 47.

The square root of 172991549 is about 13152.6251752264. The cubic root of 172991549 is about 557.1963922979.

The spelling of 172991549 in words is "one hundred seventy-two million, nine hundred ninety-one thousand, five hundred forty-nine".