643937297 has 4 divisors (see below), whose sum is σ = 645636720. Its totient is φ = 642237876.

The previous prime is 643937291. The next prime is 643937347. The reversal of 643937297 is 792739346.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 643937297 - 2¹² = 643933201 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643937291) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 849143 + ... + 849900.

It is an arithmetic number, because the mean of its divisors is an integer number (161409180).

Almost surely, 2^643937297 is an apocalyptic number.

It is an amenable number.

643937297 is a deficient number, since it is larger than the sum of its proper divisors (1699423).

643937297 is a wasteful number, since it uses less digits than its factorization.

643937297 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1699422.

The product of its digits is 1714608, while the sum is 50.

The square root of 643937297 is about 25375.9196286558. The cubic root of 643937297 is about 863.5374829484.

The spelling of 643937297 in words is "six hundred forty-three million, nine hundred thirty-seven thousand, two hundred ninety-seven".