643194974 has 4 divisors (see below), whose sum is σ = 964792464. Its totient is φ = 321597486.

The previous prime is 643194947. The next prime is 643194991. The reversal of 643194974 is 479491346.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 479491346 = 2 ⋅239745673.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160798742 + ... + 160798745.

It is an arithmetic number, because the mean of its divisors is an integer number (241198116).

Almost surely, 2^643194974 is an apocalyptic number.

643194974 is a deficient number, since it is larger than the sum of its proper divisors (321597490).

643194974 is a wasteful number, since it uses less digits than its factorization.

643194974 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 321597489.

The product of its digits is 653184, while the sum is 47.

The square root of 643194974 is about 25361.2888868054. The cubic root of 643194974 is about 863.2055302271.

The spelling of 643194974 in words is "six hundred forty-three million, one hundred ninety-four thousand, nine hundred seventy-four".