665772101 has 4 divisors (see below), whose sum is σ = 665966304. Its totient is φ = 665577900.

The previous prime is 665772073. The next prime is 665772113. The reversal of 665772101 is 101277566.

665772101 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-665772101 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 (665772161) 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, 91865 + ... + 98846.

It is an arithmetic number, because the mean of its divisors is an integer number (166491576).

Almost surely, 2^665772101 is an apocalyptic number.

It is an amenable number.

665772101 is a deficient number, since it is larger than the sum of its proper divisors (194203).

665772101 is a wasteful number, since it uses less digits than its factorization.

665772101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 194202.

The product of its (nonzero) digits is 17640, while the sum is 35.

The square root of 665772101 is about 25802.5599698945. The cubic root of 665772101 is about 873.1895522903.

The spelling of 665772101 in words is "six hundred sixty-five million, seven hundred seventy-two thousand, one hundred one".