1644553457 has 2 divisors, whose sum is σ = 1644553458. Its totient is φ = 1644553456.

The previous prime is 1644553381. The next prime is 1644553459. The reversal of 1644553457 is 7543554461.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1581573361 + 62980096 = 39769^2 + 7936^2 .

It is an emirp because it is prime and its reverse (7543554461) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1644553457 - 2¹⁶ = 1644487921 is a prime.

Together with 1644553459, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1644553459) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 822276728 + 822276729.

It is an arithmetic number, because the mean of its divisors is an integer number (822276729).

Almost surely, 2^1644553457 is an apocalyptic number.

It is an amenable number.

1644553457 is a deficient number, since it is larger than the sum of its proper divisors (1).

1644553457 is an equidigital number, since it uses as much as digits as its factorization.

1644553457 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1008000, while the sum is 44.

The square root of 1644553457 is about 40553.0942962433. The cubic root of 1644553457 is about 1180.3641165411.

The spelling of 1644553457 in words is "one billion, six hundred forty-four million, five hundred fifty-three thousand, four hundred fifty-seven".