643654635 has 32 divisors (see below), whose sum is σ = 1111719168. Its totient is φ = 316118400.

The previous prime is 643654607. The next prime is 643654639. The reversal of 643654635 is 536456346.

It is a happy number.

It is not a de Polignac number, because 643654635 - 2⁵ = 643654603 is a prime.

It is not an unprimeable number, because it can be changed into a prime (643654639) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 82660 + ... + 90110.

It is an arithmetic number, because the mean of its divisors is an integer number (34741224).

Almost surely, 2^643654635 is an apocalyptic number.

643654635 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

643654635 is a deficient number, since it is larger than the sum of its proper divisors (468064533).

643654635 is a wasteful number, since it uses less digits than its factorization.

643654635 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7915.

The product of its digits is 777600, while the sum is 42.

The square root of 643654635 is about 25370.3495245927. The cubic root of 643654635 is about 863.4111119715.

The spelling of 643654635 in words is "six hundred forty-three million, six hundred fifty-four thousand, six hundred thirty-five".