643746154 has 4 divisors (see below), whose sum is σ = 965619234. Its totient is φ = 321873076.

The previous prime is 643746143. The next prime is 643746199. The reversal of 643746154 is 451647346.

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., 358913025 + 284833129 = 18945^2 + 16877^2 .

It is a super-2 number, since 2×643746154² = 828818221579583432, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160936537 + ... + 160936540.

Almost surely, 2^643746154 is an apocalyptic number.

643746154 is a deficient number, since it is larger than the sum of its proper divisors (321873080).

643746154 is a wasteful number, since it uses less digits than its factorization.

643746154 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 321873079.

The product of its digits is 241920, while the sum is 40.

The square root of 643746154 is about 25372.1531210893. The cubic root of 643746154 is about 863.4520318336.

The spelling of 643746154 in words is "six hundred forty-three million, seven hundred forty-six thousand, one hundred fifty-four".