66623644 has 12 divisors (see below), whose sum is σ = 116691624. Its totient is φ = 33283184.

The previous prime is 66623639. The next prime is 66623677. The reversal of 66623644 is 44632666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1414 + ... + 11629.

It is an arithmetic number, because the mean of its divisors is an integer number (9724302).

Almost surely, 2^66623644 is an apocalyptic number.

It is an amenable number.

66623644 is a deficient number, since it is larger than the sum of its proper divisors (50067980).

66623644 is a wasteful number, since it uses less digits than its factorization.

66623644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14324 (or 14322 counting only the distinct ones).

The product of its digits is 124416, while the sum is 37.

The square root of 66623644 is about 8162.3307945709. The cubic root of 66623644 is about 405.3928900854.

It can be divided in two parts, 666 and 23644, that added together give a triangular number (24310 = T₂₂₀).

The spelling of 66623644 in words is "sixty-six million, six hundred twenty-three thousand, six hundred forty-four".