66476821 has 2 divisors, whose sum is σ = 66476822. Its totient is φ = 66476820.

The previous prime is 66476791. The next prime is 66476833. The reversal of 66476821 is 12867466.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 58354321 + 8122500 = 7639^2 + 2850^2 .

It is a cyclic number.

It is not a de Polignac number, because 66476821 - 2¹⁹ = 65952533 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66416821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33238410 + 33238411.

It is an arithmetic number, because the mean of its divisors is an integer number (33238411).

Almost surely, 2^66476821 is an apocalyptic number.

It is an amenable number.

66476821 is a deficient number, since it is larger than the sum of its proper divisors (1).

66476821 is an equidigital number, since it uses as much as digits as its factorization.

66476821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 96768, while the sum is 40.

The square root of 66476821 is about 8153.3318956118. The cubic root of 66476821 is about 405.0948738767.

The spelling of 66476821 in words is "sixty-six million, four hundred seventy-six thousand, eight hundred twenty-one".