38910821 has 2 divisors, whose sum is σ = 38910822. Its totient is φ = 38910820.

The previous prime is 38910811. The next prime is 38910847. The reversal of 38910821 is 12801983.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 38613796 + 297025 = 6214^2 + 545^2 .

It is an emirp because it is prime and its reverse (12801983) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 38910821 - 2⁶ = 38910757 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (38910811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19455410 + 19455411.

It is an arithmetic number, because the mean of its divisors is an integer number (19455411).

Almost surely, 2^38910821 is an apocalyptic number.

It is an amenable number.

38910821 is a deficient number, since it is larger than the sum of its proper divisors (1).

38910821 is an equidigital number, since it uses as much as digits as its factorization.

38910821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3456, while the sum is 32.

The square root of 38910821 is about 6237.8538777371. The cubic root of 38910821 is about 338.8624642579.

The spelling of 38910821 in words is "thirty-eight million, nine hundred ten thousand, eight hundred twenty-one".