172397778901 has 4 divisors (see below), whose sum is σ = 174825916704. Its totient is φ = 169969641100.

The previous prime is 172397778899. The next prime is 172397778919. The reversal of 172397778901 is 109877793271.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 109877793271 = 11117 ⋅9883763.

It is a cyclic number.

It is not a de Polignac number, because 172397778901 - 2¹ = 172397778899 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 172397778901.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (172397778401) 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, 1214068795 + ... + 1214068936.

It is an arithmetic number, because the mean of its divisors is an integer number (43706479176).

Almost surely, 2^172397778901 is an apocalyptic number.

It is an amenable number.

172397778901 is a deficient number, since it is larger than the sum of its proper divisors (2428137803).

172397778901 is an equidigital number, since it uses as much as digits as its factorization.

172397778901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2428137802.

The product of its (nonzero) digits is 9335088, while the sum is 61.

The spelling of 172397778901 in words is "one hundred seventy-two billion, three hundred ninety-seven million, seven hundred seventy-eight thousand, nine hundred one".