73665521 has 2 divisors, whose sum is σ = 73665522. Its totient is φ = 73665520.

The previous prime is 73665509. The next prime is 73665523. The reversal of 73665521 is 12556637.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 58369600 + 15295921 = 7640^2 + 3911^2 .

It is an emirp because it is prime and its reverse (12556637) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 73665521 - 2¹⁰ = 73664497 is a prime.

Together with 73665523, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (73665523) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36832760 + 36832761.

It is an arithmetic number, because the mean of its divisors is an integer number (36832761).

Almost surely, 2^73665521 is an apocalyptic number.

It is an amenable number.

73665521 is a deficient number, since it is larger than the sum of its proper divisors (1).

73665521 is an equidigital number, since it uses as much as digits as its factorization.

73665521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 37800, while the sum is 35.

The square root of 73665521 is about 8582.8620517867. The cubic root of 73665521 is about 419.2001424772.

The spelling of 73665521 in words is "seventy-three million, six hundred sixty-five thousand, five hundred twenty-one".