1992639809 has 2 divisors, whose sum is σ = 1992639810. Its totient is φ = 1992639808.

The previous prime is 1992639787. The next prime is 1992639833. The reversal of 1992639809 is 9089362991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1294200625 + 698439184 = 35975^2 + 26428^2 .

It is an emirp because it is prime and its reverse (9089362991) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1992639809 is a prime.

It is a super-2 number, since 2×1992639809² = 7941226816823112962, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1992639889) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 996319904 + 996319905.

It is an arithmetic number, because the mean of its divisors is an integer number (996319905).

Almost surely, 2^1992639809 is an apocalyptic number.

It is an amenable number.

1992639809 is a deficient number, since it is larger than the sum of its proper divisors (1).

1992639809 is an equidigital number, since it uses as much as digits as its factorization.

1992639809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1889568, while the sum is 56.

The square root of 1992639809 is about 44638.9942651041. The cubic root of 1992639809 is about 1258.3736068315.

The spelling of 1992639809 in words is "one billion, nine hundred ninety-two million, six hundred thirty-nine thousand, eight hundred nine".