65878619221 has 2 divisors, whose sum is σ = 65878619222. Its totient is φ = 65878619220.

The previous prime is 65878619197. The next prime is 65878619263. The reversal of 65878619221 is 12291687856.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 56221626321 + 9656992900 = 237111^2 + 98270^2 .

It is a cyclic number.

It is not a de Polignac number, because 65878619221 - 2²⁷ = 65744401493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (65878619291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32939309610 + 32939309611.

It is an arithmetic number, because the mean of its divisors is an integer number (32939309611).

Almost surely, 2^65878619221 is an apocalyptic number.

It is an amenable number.

65878619221 is a deficient number, since it is larger than the sum of its proper divisors (1).

65878619221 is an equidigital number, since it uses as much as digits as its factorization.

65878619221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2903040, while the sum is 55.

The spelling of 65878619221 in words is "sixty-five billion, eight hundred seventy-eight million, six hundred nineteen thousand, two hundred twenty-one".