66553220 has 24 divisors (see below), whose sum is σ = 141048600. Its totient is φ = 26376192.

The previous prime is 66553217. The next prime is 66553247. The reversal of 66553220 is 2235566.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 228484 + 66324736 = 478^2 + 8144^2 .

It is a super-3 number, since 3×66553220³ (a number of 24 digits) contains 333 as substring.

It is a nialpdrome in base 10.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13085 + ... + 17444.

It is an arithmetic number, because the mean of its divisors is an integer number (5877025).

Almost surely, 2^66553220 is an apocalyptic number.

It is an amenable number.

66553220 is an abundant number, since it is smaller than the sum of its proper divisors (74495380).

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

66553220 is a wasteful number, since it uses less digits than its factorization.

66553220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30647 (or 30645 counting only the distinct ones).

The product of its (nonzero) digits is 10800, while the sum is 29.

The square root of 66553220 is about 8158.0156901050. The cubic root of 66553220 is about 405.2500006026.

Adding to 66553220 its reverse (2235566), we get a palindrome (68788786).

The spelling of 66553220 in words is "sixty-six million, five hundred fifty-three thousand, two hundred twenty".