172078121329 has 9 divisors (see below), whose sum is σ = 173661719179. Its totient is φ = 170508845920.

The previous prime is 172078121311. The next prime is 172078121339. The reversal of 172078121329 is 923121870271.

The square root of 172078121329 is 414823.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 3032154225 + 169045967104 = 55065^2 + 411152^2 .

It is not a de Polignac number, because 172078121329 - 2¹¹ = 172078119281 is a prime.

It is a super-2 number, since 2×172078121329² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (172078121339) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 46873164 + ... + 46876834.

Almost surely, 2^172078121329 is an apocalyptic number.

172078121329 is the 414823-rd square number.

172078121329 is the 207412-nd centered octagonal number.

It is an amenable number.

172078121329 is a deficient number, since it is larger than the sum of its proper divisors (1583597850).

172078121329 is an frugal number, since it uses more digits than its factorization.

172078121329 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7568 (or 3784 counting only the distinct ones).

The product of its (nonzero) digits is 84672, while the sum is 43.

The spelling of 172078121329 in words is "one hundred seventy-two billion, seventy-eight million, one hundred twenty-one thousand, three hundred twenty-nine".