67216644 has 72 divisors (see below), whose sum is σ = 186338880. Its totient is φ = 20260800.

The previous prime is 67216631. The next prime is 67216663. The reversal of 67216644 is 44661276.

67216644 is a `hidden beast` number, since 6 + 7 + 2 + 1 + 6 + 644 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 67216599 and 67216608.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 106209 + ... + 106839.

It is an arithmetic number, because the mean of its divisors is an integer number (2588040).

Almost surely, 2^67216644 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 67216644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (93169440).

67216644 is an abundant number, since it is smaller than the sum of its proper divisors (119122236).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

67216644 is a wasteful number, since it uses less digits than its factorization.

67216644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 921 (or 916 counting only the distinct ones).

The product of its digits is 48384, while the sum is 36.

The square root of 67216644 is about 8198.5757299668. The cubic root of 67216644 is about 406.5921052349.

The spelling of 67216644 in words is "sixty-seven million, two hundred sixteen thousand, six hundred forty-four".