643465541 has 2 divisors, whose sum is σ = 643465542. Its totient is φ = 643465540.

The previous prime is 643465523. The next prime is 643465577. The reversal of 643465541 is 145564346.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 464574916 + 178890625 = 21554^2 + 13375^2 .

It is a cyclic number.

It is not a de Polignac number, because 643465541 - 2¹⁸ = 643203397 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 643465495 and 643465504.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643465591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321732770 + 321732771.

It is an arithmetic number, because the mean of its divisors is an integer number (321732771).

Almost surely, 2^643465541 is an apocalyptic number.

It is an amenable number.

643465541 is a deficient number, since it is larger than the sum of its proper divisors (1).

643465541 is an equidigital number, since it uses as much as digits as its factorization.

643465541 is an evil number, because the sum of its binary digits is even.

The product of its digits is 172800, while the sum is 38.

The square root of 643465541 is about 25366.6225777103. The cubic root of 643465541 is about 863.3265522078.

The spelling of 643465541 in words is "six hundred forty-three million, four hundred sixty-five thousand, five hundred forty-one".