643646346 has 16 divisors (see below), whose sum is σ = 1471191744. Its totient is φ = 183898944.

The previous prime is 643646323. The next prime is 643646357.

643646346 is nontrivially palindromic in base 10.

It is a Harshad number since it is a multiple of its sum of digits (42), and also a Moran number because the ratio is a prime number: 15324913 = 643646346 / (6 + 4 + 3 + 6 + 4 + 6 + 3 + 4 + 6).

It is a junction number, because it is equal to n+sod(n) for n = 643646298 and 643646307.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7662415 + ... + 7662498.

It is an arithmetic number, because the mean of its divisors is an integer number (91949484).

Almost surely, 2^643646346 is an apocalyptic number.

643646346 is an abundant number, since it is smaller than the sum of its proper divisors (827545398).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

643646346 is a wasteful number, since it uses less digits than its factorization.

643646346 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15324925.

The product of its digits is 746496, while the sum is 42.

The square root of 643646346 is about 25370.1861640785. The cubic root of 643646346 is about 863.4074056125.

The spelling of 643646346 in words is "six hundred forty-three million, six hundred forty-six thousand, three hundred forty-six".