66020981 has 12 divisors (see below), whose sum is σ = 72162468. Its totient is φ = 60044544.

The previous prime is 66020963. The next prime is 66020989. The reversal of 66020981 is 18902066.

It can be written as a sum of positive squares in 6 ways, for example, as 1876900 + 64144081 = 1370^2 + 8009^2 .

It is not a de Polignac number, because 66020981 - 2¹⁸ = 65758837 is a prime.

It is a super-2 number, since 2×66020981² = 8717539864404722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66020989) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 68801 + ... + 69753.

It is an arithmetic number, because the mean of its divisors is an integer number (6013539).

Almost surely, 2^66020981 is an apocalyptic number.

It is an amenable number.

66020981 is a deficient number, since it is larger than the sum of its proper divisors (6141487).

66020981 is an equidigital number, since it uses as much as digits as its factorization.

66020981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1112 (or 1039 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 32.

The square root of 66020981 is about 8125.3295933150. The cubic root of 66020981 is about 404.1668203823.

The spelling of 66020981 in words is "sixty-six million, twenty thousand, nine hundred eighty-one".