65989517521 has 2 divisors, whose sum is σ = 65989517522. Its totient is φ = 65989517520.

The previous prime is 65989517471. The next prime is 65989517533. The reversal of 65989517521 is 12571598956.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 42973290000 + 23016227521 = 207300^2 + 151711^2 .

It is a cyclic number.

It is not a de Polignac number, because 65989517521 - 2⁷ = 65989517393 is a prime.

It is not a weakly prime, because it can be changed into another prime (65989517921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32994758760 + 32994758761.

It is an arithmetic number, because the mean of its divisors is an integer number (32994758761).

Almost surely, 2^65989517521 is an apocalyptic number.

It is an amenable number.

65989517521 is a deficient number, since it is larger than the sum of its proper divisors (1).

65989517521 is an equidigital number, since it uses as much as digits as its factorization.

65989517521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6804000, while the sum is 58.

The spelling of 65989517521 in words is "sixty-five billion, nine hundred eighty-nine million, five hundred seventeen thousand, five hundred twenty-one".