66540531 has 4 divisors (see below), whose sum is σ = 88720712. Its totient is φ = 44360352.

The previous prime is 66540521. The next prime is 66540553. The reversal of 66540531 is 13504566.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 66540531 - 2¹⁷ = 66409459 is a prime.

It is a super-2 number, since 2×66540531² = 8855284531523922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66540511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11090086 + ... + 11090091.

It is an arithmetic number, because the mean of its divisors is an integer number (22180178).

Almost surely, 2^66540531 is an apocalyptic number.

66540531 is a deficient number, since it is larger than the sum of its proper divisors (22180181).

66540531 is a wasteful number, since it uses less digits than its factorization.

66540531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22180180.

The product of its (nonzero) digits is 10800, while the sum is 30.

The square root of 66540531 is about 8157.2379516599. The cubic root of 66540531 is about 405.2242440522.

The spelling of 66540531 in words is "sixty-six million, five hundred forty thousand, five hundred thirty-one".