644169241 has 4 divisors (see below), whose sum is σ = 645360484. Its totient is φ = 642978000.

The previous prime is 644169233. The next prime is 644169247. The reversal of 644169241 is 142961446.

644169241 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.

It can be written as a sum of positive squares in 2 ways, for example, as 500864400 + 143304841 = 22380^2 + 11971^2 .

It is a cyclic number.

It is not a de Polignac number, because 644169241 - 2³ = 644169233 is a prime.

It is a super-2 number, since 2×644169241² = 829908022101032162, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 644169241.

It is not an unprimeable number, because it can be changed into a prime (644169247) 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, 594810 + ... + 595891.

It is an arithmetic number, because the mean of its divisors is an integer number (161340121).

Almost surely, 2^644169241 is an apocalyptic number.

It is an amenable number.

644169241 is a deficient number, since it is larger than the sum of its proper divisors (1191243).

644169241 is a wasteful number, since it uses less digits than its factorization.

644169241 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1191242.

The product of its digits is 41472, while the sum is 37.

The square root of 644169241 is about 25380.4893766846. The cubic root of 644169241 is about 863.6411515796.

It can be divided in two parts, 64416924 and 1, that added together give a triangular number (64416925 = T₁₁₃₅₀).

The spelling of 644169241 in words is "six hundred forty-four million, one hundred sixty-nine thousand, two hundred forty-one".