66720739 has 2 divisors, whose sum is σ = 66720740. Its totient is φ = 66720738.

The previous prime is 66720727. The next prime is 66720743. The reversal of 66720739 is 93702766.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66720739 - 2⁵ = 66720707 is a prime.

It is a super-2 number, since 2×66720739² = 8903314025412242, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (66720439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33360369 + 33360370.

It is an arithmetic number, because the mean of its divisors is an integer number (33360370).

Almost surely, 2^66720739 is an apocalyptic number.

66720739 is a deficient number, since it is larger than the sum of its proper divisors (1).

66720739 is an equidigital number, since it uses as much as digits as its factorization.

66720739 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 95256, while the sum is 40.

The square root of 66720739 is about 8168.2763787717. The cubic root of 66720739 is about 405.5897296974.

The spelling of 66720739 in words is "sixty-six million, seven hundred twenty thousand, seven hundred thirty-nine".