66912621 has 4 divisors (see below), whose sum is σ = 89216832. Its totient is φ = 44608412.

The previous prime is 66912607. The next prime is 66912647. The reversal of 66912621 is 12621966.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 66912621 - 2¹¹ = 66910573 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66912721) 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, 11152101 + ... + 11152106.

It is an arithmetic number, because the mean of its divisors is an integer number (22304208).

Almost surely, 2^66912621 is an apocalyptic number.

It is an amenable number.

66912621 is a deficient number, since it is larger than the sum of its proper divisors (22304211).

66912621 is a wasteful number, since it uses less digits than its factorization.

66912621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22304210.

The product of its digits is 7776, while the sum is 33.

The square root of 66912621 is about 8180.0135085463. The cubic root of 66912621 is about 405.9781690479.

The spelling of 66912621 in words is "sixty-six million, nine hundred twelve thousand, six hundred twenty-one".