66975731 has 2 divisors, whose sum is σ = 66975732. Its totient is φ = 66975730.

The previous prime is 66975721. The next prime is 66975757. The reversal of 66975731 is 13757966.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66975731 - 2¹⁰ = 66974707 is a prime.

It is a super-2 number, since 2×66975731² = 8971497085968722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (66975721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33487865 + 33487866.

It is an arithmetic number, because the mean of its divisors is an integer number (33487866).

Almost surely, 2^66975731 is an apocalyptic number.

66975731 is a deficient number, since it is larger than the sum of its proper divisors (1).

66975731 is an equidigital number, since it uses as much as digits as its factorization.

66975731 is an evil number, because the sum of its binary digits is even.

The product of its digits is 238140, while the sum is 44.

The square root of 66975731 is about 8183.8701724795. The cubic root of 66975731 is about 406.1057644651.

The spelling of 66975731 in words is "sixty-six million, nine hundred seventy-five thousand, seven hundred thirty-one".