66203557 has 6 divisors (see below), whose sum is σ = 77012358. Its totient is φ = 56745864.

The previous prime is 66203537. The next prime is 66203573. The reversal of 66203557 is 75530266.

It can be written as a sum of positive squares in only one way, i.e., 41293476 + 24910081 = 6426^2 + 4991^2 .

It is not a de Polignac number, because 66203557 - 2¹⁹ = 65679269 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66203537) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 675498 + ... + 675595.

It is an arithmetic number, because the mean of its divisors is an integer number (12835393).

Almost surely, 2^66203557 is an apocalyptic number.

It is an amenable number.

66203557 is a deficient number, since it is larger than the sum of its proper divisors (10808801).

66203557 is a wasteful number, since it uses less digits than its factorization.

66203557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1351107 (or 1351100 counting only the distinct ones).

The product of its (nonzero) digits is 37800, while the sum is 34.

The square root of 66203557 is about 8136.5568270614. The cubic root of 66203557 is about 404.5390416738.

The spelling of 66203557 in words is "sixty-six million, two hundred three thousand, five hundred fifty-seven".