3728709221 has 2 divisors, whose sum is σ = 3728709222. Its totient is φ = 3728709220.

The previous prime is 3728709209. The next prime is 3728709223. The reversal of 3728709221 is 1229078273.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2488612996 + 1240096225 = 49886^2 + 35215^2 .

It is an emirp because it is prime and its reverse (1229078273) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 3728709221 - 2¹⁰ = 3728708197 is a prime.

It is a super-3 number, since 3×3728709221³ (a number of 30 digits) contains 333 as substring.

Together with 3728709223, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3728709223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1864354610 + 1864354611.

It is an arithmetic number, because the mean of its divisors is an integer number (1864354611).

Almost surely, 2^3728709221 is an apocalyptic number.

It is an amenable number.

3728709221 is a deficient number, since it is larger than the sum of its proper divisors (1).

3728709221 is an equidigital number, since it uses as much as digits as its factorization.

3728709221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 84672, while the sum is 41.

The square root of 3728709221 is about 61063.1576402662. The cubic root of 3728709221 is about 1550.6704308884.

The spelling of 3728709221 in words is "three billion, seven hundred twenty-eight million, seven hundred nine thousand, two hundred twenty-one".