66609504 has 72 divisors (see below), whose sum is σ = 204003072. Its totient is φ = 20494080.

The previous prime is 66609503. The next prime is 66609523. The reversal of 66609504 is 40590666.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66609503) 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, 5152 + ... + 12639.

It is an arithmetic number, because the mean of its divisors is an integer number (2833376).

Almost surely, 2^66609504 is an apocalyptic number.

It is an amenable number.

66609504 is an abundant number, since it is smaller than the sum of its proper divisors (137393568).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66609504 is a wasteful number, since it uses less digits than its factorization.

66609504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17820 (or 17809 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 36.

The square root of 66609504 is about 8161.4645744499. The cubic root of 66609504 is about 405.3642082706.

The spelling of 66609504 in words is "sixty-six million, six hundred nine thousand, five hundred four".