73660021 has 2 divisors, whose sum is σ = 73660022. Its totient is φ = 73660020.

The previous prime is 73660019. The next prime is 73660033. The reversal of 73660021 is 12006637.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 45037521 + 28622500 = 6711^2 + 5350^2 .

It is a cyclic number.

It is not a de Polignac number, because 73660021 - 2¹ = 73660019 is a prime.

It is a super-3 number, since 3×73660021³ (a number of 25 digits) contains 333 as substring.

Together with 73660019, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (73660051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36830010 + 36830011.

It is an arithmetic number, because the mean of its divisors is an integer number (36830011).

Almost surely, 2^73660021 is an apocalyptic number.

It is an amenable number.

73660021 is a deficient number, since it is larger than the sum of its proper divisors (1).

73660021 is an equidigital number, since it uses as much as digits as its factorization.

73660021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1512, while the sum is 25.

The square root of 73660021 is about 8582.5416398640. The cubic root of 73660021 is about 419.1897094726.

Adding to 73660021 its reverse (12006637), we get a palindrome (85666658).

The spelling of 73660021 in words is "seventy-three million, six hundred sixty thousand, twenty-one".