1938101021 has 2 divisors, whose sum is σ = 1938101022. Its totient is φ = 1938101020.

The previous prime is 1938100973. The next prime is 1938101029. The reversal of 1938101021 is 1201018391.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1569268996 + 368832025 = 39614^2 + 19205^2 .

It is an emirp because it is prime and its reverse (1201018391) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1938101021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1938101029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 969050510 + 969050511.

It is an arithmetic number, because the mean of its divisors is an integer number (969050511).

Almost surely, 2^1938101021 is an apocalyptic number.

It is an amenable number.

1938101021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1938101021 is an equidigital number, since it uses as much as digits as its factorization.

1938101021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432, while the sum is 26.

The square root of 1938101021 is about 44023.8687645691. The cubic root of 1938101021 is about 1246.7866309660.

The spelling of 1938101021 in words is "one billion, nine hundred thirty-eight million, one hundred one thousand, twenty-one".