1971942389 has 2 divisors, whose sum is σ = 1971942390. Its totient is φ = 1971942388.

The previous prime is 1971942383. The next prime is 1971942439. The reversal of 1971942389 is 9832491791.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1093294225 + 878648164 = 33065^2 + 29642^2 .

It is a cyclic number.

It is not a de Polignac number, because 1971942389 - 2²⁸ = 1703506933 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1971942389.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1971942383) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 985971194 + 985971195.

It is an arithmetic number, because the mean of its divisors is an integer number (985971195).

Almost surely, 2^1971942389 is an apocalyptic number.

It is an amenable number.

1971942389 is a deficient number, since it is larger than the sum of its proper divisors (1).

1971942389 is an equidigital number, since it uses as much as digits as its factorization.

1971942389 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 979776, while the sum is 53.

The square root of 1971942389 is about 44406.5579503749. The cubic root of 1971942389 is about 1254.0015527115.

The spelling of 1971942389 in words is "one billion, nine hundred seventy-one million, nine hundred forty-two thousand, three hundred eighty-nine".