66987655 has 24 divisors (see below), whose sum is σ = 94720320. Its totient is φ = 45339840.

The previous prime is 66987653. The next prime is 66987689. The reversal of 66987655 is 55678966.

It is not a de Polignac number, because 66987655 - 2¹ = 66987653 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66987653) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 17625 + ... + 21085.

It is an arithmetic number, because the mean of its divisors is an integer number (3946680).

Almost surely, 2^66987655 is an apocalyptic number.

66987655 is a deficient number, since it is larger than the sum of its proper divisors (27732665).

66987655 is a wasteful number, since it uses less digits than its factorization.

66987655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3559 (or 3552 counting only the distinct ones).

The product of its digits is 2721600, while the sum is 52.

The square root of 66987655 is about 8184.5986462379. The cubic root of 66987655 is about 406.1298633326.

The spelling of 66987655 in words is "sixty-six million, nine hundred eighty-seven thousand, six hundred fifty-five".