38221721 has 2 divisors, whose sum is σ = 38221722. Its totient is φ = 38221720.

The previous prime is 38221709. The next prime is 38221723. The reversal of 38221721 is 12712283.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23629321 + 14592400 = 4861^2 + 3820^2 .

It is an emirp because it is prime and its reverse (12712283) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 38221721 - 2⁶ = 38221657 is a prime.

Together with 38221723, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (38221723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19110860 + 19110861.

It is an arithmetic number, because the mean of its divisors is an integer number (19110861).

Almost surely, 2^38221721 is an apocalyptic number.

It is an amenable number.

38221721 is a deficient number, since it is larger than the sum of its proper divisors (1).

38221721 is an equidigital number, since it uses as much as digits as its factorization.

38221721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1344, while the sum is 26.

The square root of 38221721 is about 6182.3717940609. The cubic root of 38221721 is about 336.8501507206.

The spelling of 38221721 in words is "thirty-eight million, two hundred twenty-one thousand, seven hundred twenty-one".