643750978 has 16 divisors (see below), whose sum is σ = 1047392640. Its totient is φ = 294976656.

The previous prime is 643750949. The next prime is 643750981. The reversal of 643750978 is 879057346.

It is a happy number.

643750978 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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, 85450 + ... + 92677.

It is an arithmetic number, because the mean of its divisors is an integer number (65462040).

Almost surely, 2^643750978 is an apocalyptic number.

643750978 is a deficient number, since it is larger than the sum of its proper divisors (403641662).

643750978 is a wasteful number, since it uses less digits than its factorization.

643750978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 178281.

The product of its (nonzero) digits is 1270080, while the sum is 49.

The square root of 643750978 is about 25372.2481857639. The cubic root of 643750978 is about 863.4541886269.

The spelling of 643750978 in words is "six hundred forty-three million, seven hundred fifty thousand, nine hundred seventy-eight".