641171721 has 4 divisors (see below), whose sum is σ = 854895632. Its totient is φ = 427447812.

The previous prime is 641171717. The next prime is 641171723. The reversal of 641171721 is 127171146.

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 not a de Polignac number, because 641171721 - 2² = 641171717 is a prime.

It is a super-2 number, since 2×641171721² = 822202351620203682, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (641171723) 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, 106861951 + ... + 106861956.

It is an arithmetic number, because the mean of its divisors is an integer number (213723908).

Almost surely, 2^641171721 is an apocalyptic number.

It is an amenable number.

641171721 is a deficient number, since it is larger than the sum of its proper divisors (213723911).

641171721 is a wasteful number, since it uses less digits than its factorization.

641171721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 213723910.

The product of its digits is 2352, while the sum is 30.

The square root of 641171721 is about 25321.3688611023. The cubic root of 641171721 is about 862.2994712977.

The spelling of 641171721 in words is "six hundred forty-one million, one hundred seventy-one thousand, seven hundred twenty-one".