67566721 has 8 divisors (see below), whose sum is σ = 71626464. Its totient is φ = 63516480.

The previous prime is 67566691. The next prime is 67566761. The reversal of 67566721 is 12766576.

It is a happy number.

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 67566721 - 2⁵ = 67566689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (67566761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16726 + ... + 20368.

It is an arithmetic number, because the mean of its divisors is an integer number (8953308).

Almost surely, 2^67566721 is an apocalyptic number.

It is an amenable number.

67566721 is a deficient number, since it is larger than the sum of its proper divisors (4059743).

67566721 is a wasteful number, since it uses less digits than its factorization.

67566721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4751.

The product of its digits is 105840, while the sum is 40.

The square root of 67566721 is about 8219.8978704118. The cubic root of 67566721 is about 407.2967528727.

The spelling of 67566721 in words is "sixty-seven million, five hundred sixty-six thousand, seven hundred twenty-one".