644822156057 has 2 divisors, whose sum is σ = 644822156058. Its totient is φ = 644822156056.

The previous prime is 644822156053. The next prime is 644822156177. The reversal of 644822156057 is 750651228446.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 603828460096 + 40993695961 = 777064^2 + 202469^2 .

It is a cyclic number.

It is not a de Polignac number, because 644822156057 - 2² = 644822156053 is a prime.

It is a super-2 number, since 2×644822156057² (a number of 24 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 644822155996 and 644822156014.

It is not a weakly prime, because it can be changed into another prime (644822156053) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322411078028 + 322411078029.

It is an arithmetic number, because the mean of its divisors is an integer number (322411078029).

Almost surely, 2^644822156057 is an apocalyptic number.

It is an amenable number.

644822156057 is a deficient number, since it is larger than the sum of its proper divisors (1).

644822156057 is an equidigital number, since it uses as much as digits as its factorization.

644822156057 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3225600, while the sum is 50.

The spelling of 644822156057 in words is "six hundred forty-four billion, eight hundred twenty-two million, one hundred fifty-six thousand, fifty-seven".