66815487 has 12 divisors (see below), whose sum is σ = 96789264. Its totient is φ = 44415360.

The previous prime is 66815477. The next prime is 66815501. The reversal of 66815487 is 78451866.

It is a happy number.

It is not a de Polignac number, because 66815487 - 2¹⁶ = 66749951 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66815417) 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, 7339 + ... + 13692.

It is an arithmetic number, because the mean of its divisors is an integer number (8065772).

Almost surely, 2^66815487 is an apocalyptic number.

66815487 is a deficient number, since it is larger than the sum of its proper divisors (29973777).

66815487 is a wasteful number, since it uses less digits than its factorization.

66815487 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21390 (or 21387 counting only the distinct ones).

The product of its digits is 322560, while the sum is 45.

The square root of 66815487 is about 8174.0740760040. The cubic root of 66815487 is about 405.7816272498.

The spelling of 66815487 in words is "sixty-six million, eight hundred fifteen thousand, four hundred eighty-seven".