646118197 has 4 divisors (see below), whose sum is σ = 646191520. Its totient is φ = 646044876.

The previous prime is 646118183. The next prime is 646118203. The reversal of 646118197 is 791811646.

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 a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 791811646 = 2 ⋅395905823.

It is a cyclic number.

It is not a de Polignac number, because 646118197 - 2¹⁹ = 645593909 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 (646118117) 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, 21297 + ... + 41782.

It is an arithmetic number, because the mean of its divisors is an integer number (161547880).

Almost surely, 2^646118197 is an apocalyptic number.

It is an amenable number.

646118197 is a deficient number, since it is larger than the sum of its proper divisors (73323).

646118197 is a wasteful number, since it uses less digits than its factorization.

646118197 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73322.

The product of its digits is 72576, while the sum is 43.

The square root of 646118197 is about 25418.8551473114. The cubic root of 646118197 is about 864.5112665638.

The spelling of 646118197 in words is "six hundred forty-six million, one hundred eighteen thousand, one hundred ninety-seven".