66721330 has 32 divisors (see below), whose sum is σ = 131544000. Its totient is φ = 24215232.

The previous prime is 66721301. The next prime is 66721349. The reversal of 66721330 is 3312766.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3321 + ... + 12019.

It is an arithmetic number, because the mean of its divisors is an integer number (4110750).

Almost surely, 2^66721330 is an apocalyptic number.

66721330 is a deficient number, since it is larger than the sum of its proper divisors (64822670).

66721330 is a wasteful number, since it uses less digits than its factorization.

66721330 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8778.

The product of its (nonzero) digits is 4536, while the sum is 28.

The square root of 66721330 is about 8168.3125552344. The cubic root of 66721330 is about 405.5909272402.

The spelling of 66721330 in words is "sixty-six million, seven hundred twenty-one thousand, three hundred thirty".