1643437564 has 12 divisors (see below), whose sum is σ = 2876473600. Its totient is φ = 821587968.

The previous prime is 1643437541. The next prime is 1643437567. The reversal of 1643437564 is 4657343461.

It is a self number, because there is not a number n which added to its sum of digits gives 1643437564.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1643437567) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1029 + ... + 57340.

Almost surely, 2^1643437564 is an apocalyptic number.

It is an amenable number.

1643437564 is a deficient number, since it is larger than the sum of its proper divisors (1233036036).

1643437564 is a wasteful number, since it uses less digits than its factorization.

1643437564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65412 (or 65410 counting only the distinct ones).

The product of its digits is 725760, while the sum is 43.

The square root of 1643437564 is about 40539.3335416358. Note that the first 3 decimals coincide. The cubic root of 1643437564 is about 1180.0970819293.

The spelling of 1643437564 in words is "one billion, six hundred forty-three million, four hundred thirty-seven thousand, five hundred sixty-four".