643614553 has 2 divisors, whose sum is σ = 643614554. Its totient is φ = 643614552.

The previous prime is 643614551. The next prime is 643614571. The reversal of 643614553 is 355416346.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 399880009 + 243734544 = 19997^2 + 15612^2 .

It is a cyclic number.

It is not a de Polignac number, because 643614553 - 2¹ = 643614551 is a prime.

Together with 643614551, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (643614551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321807276 + 321807277.

It is an arithmetic number, because the mean of its divisors is an integer number (321807277).

Almost surely, 2^643614553 is an apocalyptic number.

It is an amenable number.

643614553 is a deficient number, since it is larger than the sum of its proper divisors (1).

643614553 is an equidigital number, since it uses as much as digits as its factorization.

643614553 is an evil number, because the sum of its binary digits is even.

The product of its digits is 129600, while the sum is 37.

The square root of 643614553 is about 25369.5595744191. The cubic root of 643614553 is about 863.3931893358.

The spelling of 643614553 in words is "six hundred forty-three million, six hundred fourteen thousand, five hundred fifty-three".