643620413 has 4 divisors (see below), whose sum is σ = 643721568. Its totient is φ = 643519260.

The previous prime is 643620389. The next prime is 643620449. The reversal of 643620413 is 314026346.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-643620413 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643620463) 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, 40343 + ... + 53988.

It is an arithmetic number, because the mean of its divisors is an integer number (160930392).

Almost surely, 2^643620413 is an apocalyptic number.

It is an amenable number.

643620413 is a deficient number, since it is larger than the sum of its proper divisors (101155).

643620413 is an equidigital number, since it uses as much as digits as its factorization.

643620413 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101154.

The product of its (nonzero) digits is 10368, while the sum is 29.

The square root of 643620413 is about 25369.6750668983. The cubic root of 643620413 is about 863.3958096768.

Adding to 643620413 its reverse (314026346), we get a palindrome (957646759).

The spelling of 643620413 in words is "six hundred forty-three million, six hundred twenty thousand, four hundred thirteen".