66001553 has 4 divisors (see below), whose sum is σ = 66063360. Its totient is φ = 65939748.

The previous prime is 66001549. The next prime is 66001597. The reversal of 66001553 is 35510066.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 66001553 - 2² = 66001549 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66001753) 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, 29273 + ... + 31446.

It is an arithmetic number, because the mean of its divisors is an integer number (16515840).

Almost surely, 2^66001553 is an apocalyptic number.

It is an amenable number.

66001553 is a deficient number, since it is larger than the sum of its proper divisors (61807).

66001553 is a wasteful number, since it uses less digits than its factorization.

66001553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61806.

The product of its (nonzero) digits is 2700, while the sum is 26.

The square root of 66001553 is about 8124.1339846165. The cubic root of 66001553 is about 404.1271717574.

The spelling of 66001553 in words is "sixty-six million, one thousand, five hundred fifty-three".