644014239851 has 2 divisors, whose sum is σ = 644014239852. Its totient is φ = 644014239850.

The previous prime is 644014239823. The next prime is 644014239919. The reversal of 644014239851 is 158932410446.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 644014239851 - 2²⁶ = 643947130987 is a prime.

It is a super-2 number, since 2×644014239851² (a number of 24 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 644014239796 and 644014239805.

It is not a weakly prime, because it can be changed into another prime (644014259851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322007119925 + 322007119926.

It is an arithmetic number, because the mean of its divisors is an integer number (322007119926).

Almost surely, 2^644014239851 is an apocalyptic number.

644014239851 is a deficient number, since it is larger than the sum of its proper divisors (1).

644014239851 is an equidigital number, since it uses as much as digits as its factorization.

644014239851 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 829440, while the sum is 47.

The spelling of 644014239851 in words is "six hundred forty-four billion, fourteen million, two hundred thirty-nine thousand, eight hundred fifty-one".