66438793 has 2 divisors, whose sum is σ = 66438794. Its totient is φ = 66438792.

The previous prime is 66438769. The next prime is 66438809. The reversal of 66438793 is 39783466.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 53392249 + 13046544 = 7307^2 + 3612^2 .

It is a cyclic number.

It is not a de Polignac number, because 66438793 - 2²⁵ = 32884361 is a prime.

It is a super-2 number, since 2×66438793² = 8828226430593698, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (66433793) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33219396 + 33219397.

It is an arithmetic number, because the mean of its divisors is an integer number (33219397).

Almost surely, 2^66438793 is an apocalyptic number.

It is an amenable number.

66438793 is a deficient number, since it is larger than the sum of its proper divisors (1).

66438793 is an equidigital number, since it uses as much as digits as its factorization.

66438793 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 653184, while the sum is 46.

The square root of 66438793 is about 8150.9995092627. Note that the first 3 decimals coincide. The cubic root of 66438793 is about 405.0176144348.

The spelling of 66438793 in words is "sixty-six million, four hundred thirty-eight thousand, seven hundred ninety-three".