66601559 has 4 divisors (see below), whose sum is σ = 66645216. Its totient is φ = 66557904.

The previous prime is 66601553. The next prime is 66601567. The reversal of 66601559 is 95510666.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 95510666 = 2 ⋅47755333.

It is a cyclic number.

It is not a de Polignac number, because 66601559 - 2⁴ = 66601543 is a prime.

It is a super-2 number, since 2×66601559² = 8871535322460962, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66601553) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19454 + ... + 22619.

It is an arithmetic number, because the mean of its divisors is an integer number (16661304).

Almost surely, 2^66601559 is an apocalyptic number.

66601559 is a deficient number, since it is larger than the sum of its proper divisors (43657).

66601559 is a wasteful number, since it uses less digits than its factorization.

66601559 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43656.

The product of its (nonzero) digits is 48600, while the sum is 38.

The square root of 66601559 is about 8160.9778213153. The cubic root of 66601559 is about 405.3480907173.

The spelling of 66601559 in words is "sixty-six million, six hundred one thousand, five hundred fifty-nine".