66021239 has 2 divisors, whose sum is σ = 66021240. Its totient is φ = 66021238.

The previous prime is 66021187. The next prime is 66021253. The reversal of 66021239 is 93212066.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66021239 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66021269) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33010619 + 33010620.

It is an arithmetic number, because the mean of its divisors is an integer number (33010620).

Almost surely, 2^66021239 is an apocalyptic number.

66021239 is a deficient number, since it is larger than the sum of its proper divisors (1).

66021239 is an equidigital number, since it uses as much as digits as its factorization.

66021239 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3888, while the sum is 29.

The square root of 66021239 is about 8125.3454695785. The cubic root of 66021239 is about 404.1673468559.

The spelling of 66021239 in words is "sixty-six million, twenty-one thousand, two hundred thirty-nine".