644842141 has 4 divisors (see below), whose sum is σ = 646942912. Its totient is φ = 642741372.

The previous prime is 644842139. The next prime is 644842171. The reversal of 644842141 is 141248446.

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 not a de Polignac number, because 644842141 - 2¹ = 644842139 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 644842097 and 644842106.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644842111) 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, 1049925 + ... + 1050538.

It is an arithmetic number, because the mean of its divisors is an integer number (161735728).

Almost surely, 2^644842141 is an apocalyptic number.

It is an amenable number.

644842141 is a deficient number, since it is larger than the sum of its proper divisors (2100771).

644842141 is a wasteful number, since it uses less digits than its factorization.

644842141 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2100770.

The product of its digits is 24576, while the sum is 34.

The square root of 644842141 is about 25393.7421621942. The cubic root of 644842141 is about 863.9417671408.

The spelling of 644842141 in words is "six hundred forty-four million, eight hundred forty-two thousand, one hundred forty-one".