66537021 has 8 divisors (see below), whose sum is σ = 88804800. Its totient is φ = 44313632.

The previous prime is 66537017. The next prime is 66537061. The reversal of 66537021 is 12073566.

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 66537021 - 2² = 66537017 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 66537021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66537001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7425 + ... + 13718.

It is an arithmetic number, because the mean of its divisors is an integer number (11100600).

Almost surely, 2^66537021 is an apocalyptic number.

It is an amenable number.

66537021 is a deficient number, since it is larger than the sum of its proper divisors (22267779).

66537021 is a wasteful number, since it uses less digits than its factorization.

66537021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22195.

The product of its (nonzero) digits is 7560, while the sum is 30.

The square root of 66537021 is about 8157.0228024690. The cubic root of 66537021 is about 405.2171187603.

The spelling of 66537021 in words is "sixty-six million, five hundred thirty-seven thousand, twenty-one".