66539403 has 18 divisors (see below), whose sum is σ = 111805044. Its totient is φ = 38022264.

The previous prime is 66539399. The next prime is 66539449. The reversal of 66539403 is 30493566.

It is not a de Polignac number, because 66539403 - 2² = 66539399 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66539453) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 75001 + ... + 75882.

Almost surely, 2^66539403 is an apocalyptic number.

66539403 is a gapful number since it is divisible by the number (63) formed by its first and last digit.

66539403 is a deficient number, since it is larger than the sum of its proper divisors (45265641).

66539403 is a wasteful number, since it uses less digits than its factorization.

66539403 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150903 (or 150893 counting only the distinct ones).

The product of its (nonzero) digits is 58320, while the sum is 36.

The square root of 66539403 is about 8157.1688103165. The cubic root of 66539403 is about 405.2219542421.

The spelling of 66539403 in words is "sixty-six million, five hundred thirty-nine thousand, four hundred three".