66601620 has 36 divisors (see below), whose sum is σ = 202025460. Its totient is φ = 17760384.

The previous prime is 66601567. The next prime is 66601643. The reversal of 66601620 is 2610666.

It can be written as a sum of positive squares in 2 ways, for example, as 45643536 + 20958084 = 6756^2 + 4578^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 184825 + ... + 185184.

Almost surely, 2^66601620 is an apocalyptic number.

66601620 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66601620 is an abundant number, since it is smaller than the sum of its proper divisors (135423840).

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

66601620 is a wasteful number, since it uses less digits than its factorization.

66601620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 370024 (or 370019 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 27.

The square root of 66601620 is about 8160.9815586117. The cubic root of 66601620 is about 405.3482144693.

The spelling of 66601620 in words is "sixty-six million, six hundred one thousand, six hundred twenty".