38911921 has 2 divisors, whose sum is σ = 38911922. Its totient is φ = 38911920.

The previous prime is 38911919. The next prime is 38911933. The reversal of 38911921 is 12911983.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 33223696 + 5688225 = 5764^2 + 2385^2 .

It is a cyclic number.

It is not a de Polignac number, because 38911921 - 2¹ = 38911919 is a prime.

Together with 38911919, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (38911321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19455960 + 19455961.

It is an arithmetic number, because the mean of its divisors is an integer number (19455961).

Almost surely, 2^38911921 is an apocalyptic number.

It is an amenable number.

38911921 is a deficient number, since it is larger than the sum of its proper divisors (1).

38911921 is an equidigital number, since it uses as much as digits as its factorization.

38911921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3888, while the sum is 34.

The square root of 38911921 is about 6237.9420484644. The cubic root of 38911921 is about 338.8656574159.

The spelling of 38911921 in words is "thirty-eight million, nine hundred eleven thousand, nine hundred twenty-one".