641111021 has 8 divisors (see below), whose sum is σ = 679082040. Its totient is φ = 603168768.

The previous prime is 641111017. The next prime is 641111027. The reversal of 641111021 is 120111146.

It can be written as a sum of positive squares in 4 ways, for example, as 2992900 + 638118121 = 1730^2 + 25261^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 641111021 - 2² = 641111017 is a prime.

It is a super-2 number, since 2×641111021² = 822046682495324882, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641111027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 53315 + ... + 64223.

It is an arithmetic number, because the mean of its divisors is an integer number (84885255).

Almost surely, 2^641111021 is an apocalyptic number.

It is an amenable number.

641111021 is a deficient number, since it is larger than the sum of its proper divisors (37971019).

641111021 is a wasteful number, since it uses less digits than its factorization.

641111021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14383.

The product of its (nonzero) digits is 48, while the sum is 17.

The square root of 641111021 is about 25320.1702403440. The cubic root of 641111021 is about 862.2722590195.

Adding to 641111021 its reverse (120111146), we get a palindrome (761222167).

The spelling of 641111021 in words is "six hundred forty-one million, one hundred eleven thousand, twenty-one".