3666329721 has 6 divisors (see below), whose sum is σ = 5295809610. Its totient is φ = 2444219808.

The previous prime is 3666329717. The next prime is 3666329761. The reversal of 3666329721 is 1279236663.

3666329721 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 3348242496 + 318087225 = 57864^2 + 17835^2 .

It is not a de Polignac number, because 3666329721 - 2² = 3666329717 is a prime.

It is not an unprimeable number, because it can be changed into a prime (3666329761) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 203684976 + ... + 203684993.

It is an arithmetic number, because the mean of its divisors is an integer number (882634935).

Almost surely, 2^3666329721 is an apocalyptic number.

It is an amenable number.

3666329721 is a deficient number, since it is larger than the sum of its proper divisors (1629479889).

3666329721 is a wasteful number, since it uses less digits than its factorization.

3666329721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 407369975 (or 407369972 counting only the distinct ones).

The product of its digits is 489888, while the sum is 45.

The square root of 3666329721 is about 60550.2247807554. The cubic root of 3666329721 is about 1541.9744339607.

The spelling of 3666329721 in words is "three billion, six hundred sixty-six million, three hundred twenty-nine thousand, seven hundred twenty-one".