6640444457 has 2 divisors, whose sum is σ = 6640444458. Its totient is φ = 6640444456.

The previous prime is 6640444439. The next prime is 6640444507. The reversal of 6640444457 is 7544440466.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6244792576 + 395651881 = 79024^2 + 19891^2 .

It is a cyclic number.

It is not a de Polignac number, because 6640444457 - 2¹² = 6640440361 is a prime.

It is not a weakly prime, because it can be changed into another prime (6640444757) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3320222228 + 3320222229.

It is an arithmetic number, because the mean of its divisors is an integer number (3320222229).

Almost surely, 2^6640444457 is an apocalyptic number.

It is an amenable number.

6640444457 is a deficient number, since it is larger than the sum of its proper divisors (1).

6640444457 is an equidigital number, since it uses as much as digits as its factorization.

6640444457 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1290240, while the sum is 44.

The square root of 6640444457 is about 81488.9222962238. The cubic root of 6640444457 is about 1879.6012109664.

The spelling of 6640444457 in words is "six billion, six hundred forty million, four hundred forty-four thousand, four hundred fifty-seven".