1997378869 has 2 divisors, whose sum is σ = 1997378870. Its totient is φ = 1997378868.

The previous prime is 1997378813. The next prime is 1997378921. The reversal of 1997378869 is 9688737991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1959124644 + 38254225 = 44262^2 + 6185^2 .

It is an emirp because it is prime and its reverse (9688737991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1997378869 - 2¹³ = 1997370677 is a prime.

It is a super-2 number, since 2×1997378869² = 7979044692655438322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1997378069) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 998689434 + 998689435.

It is an arithmetic number, because the mean of its divisors is an integer number (998689435).

Almost surely, 2^1997378869 is an apocalyptic number.

It is an amenable number.

1997378869 is a deficient number, since it is larger than the sum of its proper divisors (1).

1997378869 is an equidigital number, since it uses as much as digits as its factorization.

1997378869 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 41150592, while the sum is 67.

The square root of 1997378869 is about 44692.0448066543. The cubic root of 1997378869 is about 1259.3704062530.

The spelling of 1997378869 in words is "one billion, nine hundred ninety-seven million, three hundred seventy-eight thousand, eight hundred sixty-nine".