643401599 has 4 divisors (see below), whose sum is σ = 644441640. Its totient is φ = 642361560.

The previous prime is 643401527. The next prime is 643401611. The reversal of 643401599 is 995104346.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-643401599 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643401509) 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, 519092 + ... + 520329.

It is an arithmetic number, because the mean of its divisors is an integer number (161110410).

Almost surely, 2^643401599 is an apocalyptic number.

643401599 is a deficient number, since it is larger than the sum of its proper divisors (1040041).

643401599 is a wasteful number, since it uses less digits than its factorization.

643401599 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1040040.

The product of its (nonzero) digits is 116640, while the sum is 41.

The square root of 643401599 is about 25365.3621894110. The cubic root of 643401599 is about 863.2979546365.

The spelling of 643401599 in words is "six hundred forty-three million, four hundred one thousand, five hundred ninety-nine".