643619 has 2 divisors, whose sum is σ = 643620. Its totient is φ = 643618.

The previous prime is 643589. The next prime is 643633. The reversal of 643619 is 916346.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-643619 is a prime.

It is a super-2 number, since 2×643619² = 828490834322, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 643591 and 643600.

It is not a weakly prime, because it can be changed into another prime (643639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321809 + 321810.

It is an arithmetic number, because the mean of its divisors is an integer number (321810).

2⁶⁴³⁶¹⁹ is an apocalyptic number.

643619 is a deficient number, since it is larger than the sum of its proper divisors (1).

643619 is an equidigital number, since it uses as much as digits as its factorization.

643619 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3888, while the sum is 29.

The square root of 643619 is about 802.2586864597. The cubic root of 643619 is about 86.3395177845.

The spelling of 643619 in words is "six hundred forty-three thousand, six hundred nineteen".