66203540 has 48 divisors (see below), whose sum is σ = 151457040. Its totient is φ = 24161280.

The previous prime is 66203537. The next prime is 66203573. The reversal of 66203540 is 4530266.

It can be written as a sum of positive squares in 8 ways, for example, as 10163344 + 56040196 = 3188^2 + 7486^2 .

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21710 + ... + 24570.

It is an arithmetic number, because the mean of its divisors is an integer number (3155355).

Almost surely, 2^66203540 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66203540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (75728520).

66203540 is an abundant number, since it is smaller than the sum of its proper divisors (85253500).

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

66203540 is a wasteful number, since it uses less digits than its factorization.

66203540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2972 (or 2970 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 26.

The square root of 66203540 is about 8136.5557823934. Note that the first 3 decimals coincide. The cubic root of 66203540 is about 404.5390070474.

The spelling of 66203540 in words is "sixty-six million, two hundred three thousand, five hundred forty".