643897974 has 8 divisors (see below), whose sum is σ = 1287795960. Its totient is φ = 214632656.

The previous prime is 643897921. The next prime is 643898027. The reversal of 643897974 is 479798346.

It is an interprime number because it is at equal distance from previous prime (643897921) and next prime (643898027).

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

643897974 is an admirable number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 53658159 + ... + 53658170.

It is an arithmetic number, because the mean of its divisors is an integer number (160974495).

Almost surely, 2^643897974 is an apocalyptic number.

643897974 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

643897974 is a wasteful number, since it uses less digits than its factorization.

643897974 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107316334.

The product of its digits is 9144576, while the sum is 57.

The square root of 643897974 is about 25375.1448074686. The cubic root of 643897974 is about 863.5199048519.

The spelling of 643897974 in words is "six hundred forty-three million, eight hundred ninety-seven thousand, nine hundred seventy-four".