643496651 has 8 divisors (see below), whose sum is σ = 742172640. Its totient is φ = 546507648.

The previous prime is 643496639. The next prime is 643496653. The reversal of 643496651 is 156694346.

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

It is a cyclic number.

It is not a de Polignac number, because 643496651 - 2¹⁸ = 643234507 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643496653) 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, 420926 + ... + 422451.

It is an arithmetic number, because the mean of its divisors is an integer number (92771580).

Almost surely, 2^643496651 is an apocalyptic number.

643496651 is a deficient number, since it is larger than the sum of its proper divisors (98675989).

643496651 is a wasteful number, since it uses less digits than its factorization.

643496651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 843493.

The product of its digits is 466560, while the sum is 44.

The square root of 643496651 is about 25367.2357776720. The cubic root of 643496651 is about 863.3404652326.

The spelling of 643496651 in words is "six hundred forty-three million, four hundred ninety-six thousand, six hundred fifty-one".