172729921 has 8 divisors (see below), whose sum is σ = 212590784. Its totient is φ = 136665360.

The previous prime is 172729903. The next prime is 172729951. The reversal of 172729921 is 129927271.

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

It is not a de Polignac number, because 172729921 - 2¹¹ = 172727873 is a prime.

It is not an unprimeable number, because it can be changed into a prime (172729901) 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, 948975 + ... + 949156.

It is an arithmetic number, because the mean of its divisors is an integer number (26573848).

Almost surely, 2^172729921 is an apocalyptic number.

It is an amenable number.

172729921 is a deficient number, since it is larger than the sum of its proper divisors (39860863).

172729921 is a wasteful number, since it uses less digits than its factorization.

172729921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1898151.

The product of its digits is 31752, while the sum is 40.

The square root of 172729921 is about 13142.6755647395. The cubic root of 172729921 is about 556.9153540414.

The spelling of 172729921 in words is "one hundred seventy-two million, seven hundred twenty-nine thousand, nine hundred twenty-one".