643401623 has 8 divisors (see below), whose sum is σ = 647816640. Its totient is φ = 639001440.

The previous prime is 643401611. The next prime is 643401631. The reversal of 643401623 is 326104346.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 643401623 - 2¹⁸ = 643139479 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 (643401323) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 91493 + ... + 98273.

It is an arithmetic number, because the mean of its divisors is an integer number (80977080).

Almost surely, 2^643401623 is an apocalyptic number.

643401623 is a deficient number, since it is larger than the sum of its proper divisors (4415017).

643401623 is a wasteful number, since it uses less digits than its factorization.

643401623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7417.

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

The square root of 643401623 is about 25365.3626624971. The cubic root of 643401623 is about 863.2979653707.

Adding to 643401623 its reverse (326104346), we get a palindrome (969505969).

The spelling of 643401623 in words is "six hundred forty-three million, four hundred one thousand, six hundred twenty-three".