66042521 has 8 divisors (see below), whose sum is σ = 68265480. Its totient is φ = 63842688.

The previous prime is 66042517. The next prime is 66042533. The reversal of 66042521 is 12524066.

It can be written as a sum of positive squares in 4 ways, for example, as 18156121 + 47886400 = 4261^2 + 6920^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66042521 - 2² = 66042517 is a prime.

It is a super-2 number, since 2×66042521² = 8723229160070882, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (66042551) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 125 + ... + 11493.

It is an arithmetic number, because the mean of its divisors is an integer number (8533185).

Almost surely, 2^66042521 is an apocalyptic number.

It is an amenable number.

66042521 is a deficient number, since it is larger than the sum of its proper divisors (2222959).

66042521 is a wasteful number, since it uses less digits than its factorization.

66042521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11563.

The product of its (nonzero) digits is 2880, while the sum is 26.

The square root of 66042521 is about 8126.6549699123. The cubic root of 66042521 is about 404.2107700812.

Adding to 66042521 its reverse (12524066), we get a palindrome (78566587).

The spelling of 66042521 in words is "sixty-six million, forty-two thousand, five hundred twenty-one".