1992808781 has 2 divisors, whose sum is σ = 1992808782. Its totient is φ = 1992808780.

The previous prime is 1992808709. The next prime is 1992808793. The reversal of 1992808781 is 1878082991.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1014995881 + 977812900 = 31859^2 + 31270^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1992808781 is a prime.

It is a super-2 number, since 2×1992808781² = 7942573675261411922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1992808381) 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, 996404390 + 996404391.

It is an arithmetic number, because the mean of its divisors is an integer number (996404391).

Almost surely, 2^1992808781 is an apocalyptic number.

It is an amenable number.

1992808781 is a deficient number, since it is larger than the sum of its proper divisors (1).

1992808781 is an equidigital number, since it uses as much as digits as its factorization.

1992808781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 580608, while the sum is 53.

The square root of 1992808781 is about 44640.8868751507. The cubic root of 1992808781 is about 1258.4091750418.

The spelling of 1992808781 in words is "one billion, nine hundred ninety-two million, eight hundred eight thousand, seven hundred eighty-one".