65544061621 has 2 divisors, whose sum is σ = 65544061622. Its totient is φ = 65544061620.

The previous prime is 65544061601. The next prime is 65544061651. The reversal of 65544061621 is 12616044556.

65544061621 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 64739204721 + 804856900 = 254439^2 + 28370^2 .

It is a cyclic number.

It is not a de Polignac number, because 65544061621 - 2⁵ = 65544061589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (65544061601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32772030810 + 32772030811.

It is an arithmetic number, because the mean of its divisors is an integer number (32772030811).

Almost surely, 2^65544061621 is an apocalyptic number.

It is an amenable number.

65544061621 is a deficient number, since it is larger than the sum of its proper divisors (1).

65544061621 is an equidigital number, since it uses as much as digits as its factorization.

65544061621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 172800, while the sum is 40.

The spelling of 65544061621 in words is "sixty-five billion, five hundred forty-four million, sixty-one thousand, six hundred twenty-one".