65220439778 has 54 divisors (see below), whose sum is σ = 109943393859. Its totient is φ = 29003074464.

The previous prime is 65220439771. The next prime is 65220439789. The reversal of 65220439778 is 87793402256.

It can be written as a sum of positive squares in 5 ways, for example, as 10804147249 + 54416292529 = 103943^2 + 233273^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=180583.

It is not an unprimeable number, because it can be changed into a prime (65220439771) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 136159343 + ... + 136159821.

Almost surely, 2^65220439778 is an apocalyptic number.

65220439778 is a deficient number, since it is larger than the sum of its proper divisors (44722954081).

65220439778 is an equidigital number, since it uses as much as digits as its factorization.

65220439778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1044 (or 523 counting only the distinct ones).

The product of its (nonzero) digits is 5080320, while the sum is 53.

The spelling of 65220439778 in words is "sixty-five billion, two hundred twenty million, four hundred thirty-nine thousand, seven hundred seventy-eight".