66400457 has 2 divisors, whose sum is σ = 66400458. Its totient is φ = 66400456.

The previous prime is 66400447. The next prime is 66400469. The reversal of 66400457 is 75400466.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 66113161 + 287296 = 8131^2 + 536^2 .

It is a cyclic number.

It is not a de Polignac number, because 66400457 - 2⁴ = 66400441 is a prime.

It is not a weakly prime, because it can be changed into another prime (66400427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33200228 + 33200229.

It is an arithmetic number, because the mean of its divisors is an integer number (33200229).

Almost surely, 2^66400457 is an apocalyptic number.

It is an amenable number.

66400457 is a deficient number, since it is larger than the sum of its proper divisors (1).

66400457 is an equidigital number, since it uses as much as digits as its factorization.

66400457 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20160, while the sum is 32.

The square root of 66400457 is about 8148.6475564967. The cubic root of 66400457 is about 404.9396994001.

Subtracting 66400457 from its reverse (75400466), we obtain a palindrome (9000009).

The spelling of 66400457 in words is "sixty-six million, four hundred thousand, four hundred fifty-seven".