643516642 has 16 divisors (see below), whose sum is σ = 983934432. Its totient is φ = 315580320.

The previous prime is 643516637. The next prime is 643516649. The reversal of 643516642 is 246615346.

It is a super-2 number, since 2×643516642² = 828227337061912328, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (643516649) 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, 20917 + ... + 41527.

It is an arithmetic number, because the mean of its divisors is an integer number (61495902).

Almost surely, 2^643516642 is an apocalyptic number.

643516642 is a deficient number, since it is larger than the sum of its proper divisors (340417790).

643516642 is a wasteful number, since it uses less digits than its factorization.

643516642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20913.

The product of its digits is 103680, while the sum is 37.

The square root of 643516642 is about 25367.6298065073. The cubic root of 643516642 is about 863.3494053778.

The spelling of 643516642 in words is "six hundred forty-three million, five hundred sixteen thousand, six hundred forty-two".