172740391 has 4 divisors (see below), whose sum is σ = 173800312. Its totient is φ = 171680472.

The previous prime is 172740371. The next prime is 172740397. The reversal of 172740391 is 193047271.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 193047271 = 12569 ⋅15359.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-172740391 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 (172740397) 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, 529716 + ... + 530041.

It is an arithmetic number, because the mean of its divisors is an integer number (43450078).

Almost surely, 2^172740391 is an apocalyptic number.

172740391 is a deficient number, since it is larger than the sum of its proper divisors (1059921).

172740391 is a wasteful number, since it uses less digits than its factorization.

172740391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1059920.

The product of its (nonzero) digits is 10584, while the sum is 34.

The square root of 172740391 is about 13143.0738794241. The cubic root of 172740391 is about 556.9266062628.

The spelling of 172740391 in words is "one hundred seventy-two million, seven hundred forty thousand, three hundred ninety-one".