643887647498 has 4 divisors (see below), whose sum is σ = 965831471250. Its totient is φ = 321943823748.

The previous prime is 643887647497. The next prime is 643887647539. The reversal of 643887647498 is 894746788346.

643887647498 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 491867976889 + 152019670609 = 701333^2 + 389897^2 .

It is not an unprimeable number, because it can be changed into a prime (643887647497) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160971911873 + ... + 160971911876.

Almost surely, 2^643887647498 is an apocalyptic number.

643887647498 is a deficient number, since it is larger than the sum of its proper divisors (321943823752).

643887647498 is a wasteful number, since it uses less digits than its factorization.

643887647498 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 321943823751.

The product of its digits is 1560674304, while the sum is 74.

The spelling of 643887647498 in words is "six hundred forty-three billion, eight hundred eighty-seven million, six hundred forty-seven thousand, four hundred ninety-eight".