66890986473481 has 3 divisors (see below), whose sum is σ = 66890994652173. Its totient is φ = 66890978294790.

The previous prime is 66890986473403. The next prime is 66890986473497. The reversal of 66890986473481 is 18437468909866.

The square root of 66890986473481 is 8178691.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 66890986473481 - 2¹⁷ = 66890986342409 is a prime.

It is a super-2 number, since 2×66890986473481² (a number of 28 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66890986477481) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 4089346 + ... + 12268036.

It is an arithmetic number, because the mean of its divisors is an integer number (22296998217391).

Almost surely, 2^{66890986473481} is an apocalyptic number.

66890986473481 is the 8178691-st square number.

66890986473481 is the 4089346-th centered octagonal number.

It is an amenable number.

66890986473481 is a deficient number, since it is larger than the sum of its proper divisors (8178692).

66890986473481 is an frugal number, since it uses more digits than its factorization.

66890986473481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16357382 (or 8178691 counting only the distinct ones).

The product of its (nonzero) digits is 3009871872, while the sum is 79.

The spelling of 66890986473481 in words is "sixty-six trillion, eight hundred ninety billion, nine hundred eighty-six million, four hundred seventy-three thousand, four hundred eighty-one".