66721464 has 144 divisors (see below), whose sum is σ = 203271120. Its totient is φ = 19699200.

The previous prime is 66721453. The next prime is 66721477. The reversal of 66721464 is 46412766.

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

Its product of digits (48384) is a multiple of the sum of its prime divisors (192).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 441789 + ... + 441939.

It is an arithmetic number, because the mean of its divisors is an integer number (1411605).

Almost surely, 2^66721464 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 66721464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (101635560).

66721464 is an abundant number, since it is smaller than the sum of its proper divisors (136549656).

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

66721464 is a wasteful number, since it uses less digits than its factorization.

66721464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 218 (or 192 counting only the distinct ones).

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

The square root of 66721464 is about 8168.3207576588. The cubic root of 66721464 is about 405.5911987633.

The spelling of 66721464 in words is "sixty-six million, seven hundred twenty-one thousand, four hundred sixty-four".