66523531 has 4 divisors (see below), whose sum is σ = 66571200. Its totient is φ = 66475864.

The previous prime is 66523519. The next prime is 66523543. The reversal of 66523531 is 13532566.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13532566 = 2 ⋅6766283.

It is an interprime number because it is at equal distance from previous prime (66523519) and next prime (66523543).

It is a cyclic number.

It is not a de Polignac number, because 66523531 - 2⁷ = 66523403 is a prime.

It is a super-2 number, since 2×66523531² = 8850760353415922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 66523493 and 66523502.

It is not an unprimeable number, because it can be changed into a prime (66523571) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21676 + ... + 24553.

It is an arithmetic number, because the mean of its divisors is an integer number (16642800).

Almost surely, 2^66523531 is an apocalyptic number.

66523531 is a deficient number, since it is larger than the sum of its proper divisors (47669).

66523531 is a wasteful number, since it uses less digits than its factorization.

66523531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47668.

The product of its digits is 16200, while the sum is 31.

The square root of 66523531 is about 8156.1958657207. The cubic root of 66523531 is about 405.1897317592.

The spelling of 66523531 in words is "sixty-six million, five hundred twenty-three thousand, five hundred thirty-one".