66213769 has 2 divisors, whose sum is σ = 66213770. Its totient is φ = 66213768.

The previous prime is 66213751. The next prime is 66213781. The reversal of 66213769 is 96731266.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 65286400 + 927369 = 8080^2 + 963^2 .

It is a cyclic number.

It is not a de Polignac number, because 66213769 - 2¹¹ = 66211721 is a prime.

It is a super-2 number, since 2×66213769² = 8768526410370722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (66213709) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33106884 + 33106885.

It is an arithmetic number, because the mean of its divisors is an integer number (33106885).

Almost surely, 2^66213769 is an apocalyptic number.

It is an amenable number.

66213769 is a deficient number, since it is larger than the sum of its proper divisors (1).

66213769 is an equidigital number, since it uses as much as digits as its factorization.

66213769 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 81648, while the sum is 40.

The square root of 66213769 is about 8137.1843410359. The cubic root of 66213769 is about 404.5598408598.

The spelling of 66213769 in words is "sixty-six million, two hundred thirteen thousand, seven hundred sixty-nine".