643017631 has 2 divisors, whose sum is σ = 643017632. Its totient is φ = 643017630.

The previous prime is 643017619. The next prime is 643017659. The reversal of 643017631 is 136710346.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 643017631 - 2²⁵ = 609463199 is a prime.

It is a super-2 number, since 2×643017631² = 826943347553704322, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 643017593 and 643017602.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643017671) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321508815 + 321508816.

It is an arithmetic number, because the mean of its divisors is an integer number (321508816).

Almost surely, 2^643017631 is an apocalyptic number.

643017631 is a deficient number, since it is larger than the sum of its proper divisors (1).

643017631 is an equidigital number, since it uses as much as digits as its factorization.

643017631 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9072, while the sum is 31.

The square root of 643017631 is about 25357.7923132121. The cubic root of 643017631 is about 863.1261880181.

Adding to 643017631 its reverse (136710346), we get a palindrome (779727977).

The spelling of 643017631 in words is "six hundred forty-three million, seventeen thousand, six hundred thirty-one".