66892561 has 2 divisors, whose sum is σ = 66892562. Its totient is φ = 66892560.

The previous prime is 66892549. The next prime is 66892571. The reversal of 66892561 is 16529866.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 66732561 + 160000 = 8169^2 + 400^2 .

It is a cyclic number.

It is not a de Polignac number, because 66892561 - 2¹¹ = 66890513 is a prime.

It is a super-2 number, since 2×66892561² = 8949229434277442, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (66892541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33446280 + 33446281.

It is an arithmetic number, because the mean of its divisors is an integer number (33446281).

Almost surely, 2^66892561 is an apocalyptic number.

It is an amenable number.

66892561 is a deficient number, since it is larger than the sum of its proper divisors (1).

66892561 is an equidigital number, since it uses as much as digits as its factorization.

66892561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 155520, while the sum is 43.

The square root of 66892561 is about 8178.7872572894. The cubic root of 66892561 is about 405.9375950579.

The spelling of 66892561 in words is "sixty-six million, eight hundred ninety-two thousand, five hundred sixty-one".