66303721 has 8 divisors (see below), whose sum is σ = 74013984. Its totient is φ = 58873920.

The previous prime is 66303703. The next prime is 66303737. The reversal of 66303721 is 12730366.

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 66303721 - 2¹⁹ = 65779433 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 66303721.

It is not an unprimeable number, because it can be changed into a prime (66303701) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 69616 + ... + 70561.

It is an arithmetic number, because the mean of its divisors is an integer number (9251748).

Almost surely, 2^66303721 is an apocalyptic number.

It is an amenable number.

66303721 is a deficient number, since it is larger than the sum of its proper divisors (7710263).

66303721 is a wasteful number, since it uses less digits than its factorization.

66303721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140231.

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

The square root of 66303721 is about 8142.7096841285. The cubic root of 66303721 is about 404.7429573557.

The spelling of 66303721 in words is "sixty-six million, three hundred three thousand, seven hundred twenty-one".