644161337 has 2 divisors, whose sum is σ = 644161338. Its totient is φ = 644161336.

The previous prime is 644161327. The next prime is 644161411. The reversal of 644161337 is 733161446.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 643941376 + 219961 = 25376^2 + 469^2 .

It is a cyclic number.

It is not a de Polignac number, because 644161337 - 2⁴ = 644161321 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 644161297 and 644161306.

It is not a weakly prime, because it can be changed into another prime (644161327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322080668 + 322080669.

It is an arithmetic number, because the mean of its divisors is an integer number (322080669).

Almost surely, 2^644161337 is an apocalyptic number.

It is an amenable number.

644161337 is a deficient number, since it is larger than the sum of its proper divisors (1).

644161337 is an equidigital number, since it uses as much as digits as its factorization.

644161337 is an evil number, because the sum of its binary digits is even.

The product of its digits is 36288, while the sum is 35.

The square root of 644161337 is about 25380.3336660494. Note that the first 3 decimals coincide. The cubic root of 644161337 is about 863.6376192534.

The spelling of 644161337 in words is "six hundred forty-four million, one hundred sixty-one thousand, three hundred thirty-seven".