172973855 has 4 divisors (see below), whose sum is σ = 207568632. Its totient is φ = 138379080.

The previous prime is 172973851. The next prime is 172973881. The reversal of 172973855 is 558379271.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 558379271 = 643 ⋅868397.

It is not a de Polignac number, because 172973855 - 2² = 172973851 is a prime.

It is a super-2 number, since 2×172973855² = 59839909027122050, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (172973851) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17297381 + ... + 17297390.

It is an arithmetic number, because the mean of its divisors is an integer number (51892158).

Almost surely, 2^172973855 is an apocalyptic number.

172973855 is a deficient number, since it is larger than the sum of its proper divisors (34594777).

172973855 is an equidigital number, since it uses as much as digits as its factorization.

172973855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34594776.

The product of its digits is 529200, while the sum is 47.

The square root of 172973855 is about 13151.9525166418. The cubic root of 172973855 is about 557.1773945122.

The spelling of 172973855 in words is "one hundred seventy-two million, nine hundred seventy-three thousand, eight hundred fifty-five".