66999953 has 2 divisors, whose sum is σ = 66999954. Its totient is φ = 66999952.

The previous prime is 66999923. The next prime is 66999983. The reversal of 66999953 is 35999966.

It is a balanced prime because it is at equal distance from previous prime (66999923) and next prime (66999983).

It can be written as a sum of positive squares in only one way, i.e., 64513024 + 2486929 = 8032^2 + 1577^2 .

It is a cyclic number.

It is not a de Polignac number, because 66999953 - 2⁸ = 66999697 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (66999913) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33499976 + 33499977.

It is an arithmetic number, because the mean of its divisors is an integer number (33499977).

Almost surely, 2^66999953 is an apocalyptic number.

It is an amenable number.

66999953 is a deficient number, since it is larger than the sum of its proper divisors (1).

66999953 is an equidigital number, since it uses as much as digits as its factorization.

66999953 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3542940, while the sum is 56.

The square root of 66999953 is about 8185.3499008900. The cubic root of 66999953 is about 406.1547150730.

The spelling of 66999953 in words is "sixty-six million, nine hundred ninety-nine thousand, nine hundred fifty-three".