66335621 has 8 divisors (see below), whose sum is σ = 72812064. Its totient is φ = 59933520.

The previous prime is 66335603. The next prime is 66335623. The reversal of 66335621 is 12653366.

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 66335621 - 2¹⁴ = 66319237 is a prime.

It is a super-2 number, since 2×66335621² = 8800829226911282, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66335623) 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, 16706 + ... + 20291.

It is an arithmetic number, because the mean of its divisors is an integer number (9101508).

Almost surely, 2^66335621 is an apocalyptic number.

It is an amenable number.

66335621 is a deficient number, since it is larger than the sum of its proper divisors (6476443).

66335621 is a wasteful number, since it uses less digits than its factorization.

66335621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37171.

The product of its digits is 19440, while the sum is 32.

The square root of 66335621 is about 8144.6682559819. The cubic root of 66335621 is about 404.8078568318.

Adding to 66335621 its reverse (12653366), we get a palindrome (78988987).

The spelling of 66335621 in words is "sixty-six million, three hundred thirty-five thousand, six hundred twenty-one".