1643961383 has 2 divisors, whose sum is σ = 1643961384. Its totient is φ = 1643961382.

The previous prime is 1643961373. The next prime is 1643961401. The reversal of 1643961383 is 3831693461.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1643961383 - 2⁸ = 1643961127 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1643961373) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 821980691 + 821980692.

It is an arithmetic number, because the mean of its divisors is an integer number (821980692).

Almost surely, 2^1643961383 is an apocalyptic number.

1643961383 is a deficient number, since it is larger than the sum of its proper divisors (1).

1643961383 is an equidigital number, since it uses as much as digits as its factorization.

1643961383 is an evil number, because the sum of its binary digits is even.

The product of its digits is 279936, while the sum is 44.

The square root of 1643961383 is about 40545.7936535962. The cubic root of 1643961383 is about 1180.2224475293. Note that the first 3 decimals are identical.

The spelling of 1643961383 in words is "one billion, six hundred forty-three million, nine hundred sixty-one thousand, three hundred eighty-three".