1938919121 has 2 divisors, whose sum is σ = 1938919122. Its totient is φ = 1938919120.

The previous prime is 1938919117. The next prime is 1938919127. The reversal of 1938919121 is 1219198391.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 981944896 + 956974225 = 31336^2 + 30935^2 .

It is an emirp because it is prime and its reverse (1219198391) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1938919121 - 2² = 1938919117 is a prime.

It is not a weakly prime, because it can be changed into another prime (1938919127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 969459560 + 969459561.

It is an arithmetic number, because the mean of its divisors is an integer number (969459561).

Almost surely, 2^1938919121 is an apocalyptic number.

It is an amenable number.

1938919121 is a deficient number, since it is larger than the sum of its proper divisors (1).

1938919121 is an equidigital number, since it uses as much as digits as its factorization.

1938919121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 34992, while the sum is 44.

The square root of 1938919121 is about 44033.1593347559. The cubic root of 1938919121 is about 1246.9620350768.

The spelling of 1938919121 in words is "one billion, nine hundred thirty-eight million, nine hundred nineteen thousand, one hundred twenty-one".