1644698426 has 24 divisors (see below), whose sum is σ = 2890802196. Its totient is φ = 699720000.

The previous prime is 1644698423. The next prime is 1644698437. The reversal of 1644698426 is 6248964461.

It can be written as a sum of positive squares in 2 ways, for example, as 1354166401 + 290532025 = 36799^2 + 17045^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1644698423) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 47825 + ... + 74676.

Almost surely, 2^1644698426 is an apocalyptic number.

1644698426 is a deficient number, since it is larger than the sum of its proper divisors (1246103770).

1644698426 is a wasteful number, since it uses less digits than its factorization.

1644698426 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 122654 (or 122647 counting only the distinct ones).

The product of its digits is 1990656, while the sum is 50.

The square root of 1644698426 is about 40554.8816543705. The cubic root of 1644698426 is about 1180.3987989402.

The spelling of 1644698426 in words is "one billion, six hundred forty-four million, six hundred ninety-eight thousand, four hundred twenty-six".