66213553 has 12 divisors (see below), whose sum is σ = 78665472. Its totient is φ = 55545000.

The previous prime is 66213541. The next prime is 66213569. The reversal of 66213553 is 35531266.

It is a de Polignac number, because none of the positive numbers 2^k-66213553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66213503) 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, 12073 + ... + 16678.

It is an arithmetic number, because the mean of its divisors is an integer number (6555456).

Almost surely, 2^66213553 is an apocalyptic number.

It is an amenable number.

66213553 is a deficient number, since it is larger than the sum of its proper divisors (12451919).

66213553 is a wasteful number, since it uses less digits than its factorization.

66213553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28812 (or 28805 counting only the distinct ones).

The product of its digits is 16200, while the sum is 31.

The square root of 66213553 is about 8137.1710686208. The cubic root of 66213553 is about 404.5594009462.

It can be divided in two parts, 66213 and 553, that added together give a palindrome (66766).

The spelling of 66213553 in words is "sixty-six million, two hundred thirteen thousand, five hundred fifty-three".