641221613 has 8 divisors (see below), whose sum is σ = 654327288. Its totient is φ = 628153344.

The previous prime is 641221597. The next prime is 641221621. The reversal of 641221613 is 316122146.

641221613 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 107288164 + 533933449 = 10358^2 + 23107^2 .

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 641221613 - 2⁴ = 641221597 is a prime.

It is a super-2 number, since 2×641221613² = 822330313956643538, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641241613) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26681 + ... + 44657.

It is an arithmetic number, because the mean of its divisors is an integer number (81790911).

Almost surely, 2^641221613 is an apocalyptic number.

It is an amenable number.

641221613 is a deficient number, since it is larger than the sum of its proper divisors (13105675).

641221613 is a wasteful number, since it uses less digits than its factorization.

641221613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18703.

The product of its digits is 1728, while the sum is 26.

The square root of 641221613 is about 25322.3540177449. The cubic root of 641221613 is about 862.3218369802.

Adding to 641221613 its reverse (316122146), we get a palindrome (957343759).

The spelling of 641221613 in words is "six hundred forty-one million, two hundred twenty-one thousand, six hundred thirteen".