643423995 has 12 divisors (see below), whose sum is σ = 1115268336. Its totient is φ = 343159440.

The previous prime is 643423993. The next prime is 643423997. The reversal of 643423995 is 599324346.

It is an interprime number because it is at equal distance from previous prime (643423993) and next prime (643423997).

It is not a de Polignac number, because 643423995 - 2¹ = 643423993 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 14298311 = 643423995 / (6 + 4 + 3 + 4 + 2 + 3 + 9 + 9 + 5).

It is a self number, because there is not a number n which added to its sum of digits gives 643423995.

It is not an unprimeable number, because it can be changed into a prime (643423993) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7149111 + ... + 7149200.

It is an arithmetic number, because the mean of its divisors is an integer number (92939028).

Almost surely, 2^643423995 is an apocalyptic number.

643423995 is a deficient number, since it is larger than the sum of its proper divisors (471844341).

643423995 is a wasteful number, since it uses less digits than its factorization.

643423995 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14298322 (or 14298319 counting only the distinct ones).

The product of its digits is 699840, while the sum is 45.

The square root of 643423995 is about 25365.8036537382. The cubic root of 643423995 is about 863.3079712921.

The spelling of 643423995 in words is "six hundred forty-three million, four hundred twenty-three thousand, nine hundred ninety-five".