643939077 has 8 divisors (see below), whose sum is σ = 871400416. Its totient is φ = 422885232.

The previous prime is 643939063. The next prime is 643939097. The reversal of 643939077 is 770939346.

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

It is not a de Polignac number, because 643939077 - 2⁸ = 643938821 is a prime.

It is a super-2 number, since 2×643939077² = 829315069775223858, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643939097) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1601638 + ... + 1602039.

It is an arithmetic number, because the mean of its divisors is an integer number (108925052).

Almost surely, 2^643939077 is an apocalyptic number.

643939077 is a gapful number since it is divisible by the number (67) formed by its first and last digit.

It is an amenable number.

643939077 is a deficient number, since it is larger than the sum of its proper divisors (227461339).

643939077 is a wasteful number, since it uses less digits than its factorization.

643939077 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3203747.

The product of its (nonzero) digits is 857304, while the sum is 48.

The square root of 643939077 is about 25375.9547012521. The cubic root of 643939077 is about 863.5382786238.

The spelling of 643939077 in words is "six hundred forty-three million, nine hundred thirty-nine thousand, seventy-seven".