2019631681 has 2 divisors, whose sum is σ = 2019631682. Its totient is φ = 2019631680.

The previous prime is 2019631661. The next prime is 2019631693. The reversal of 2019631681 is 1861369102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2005606656 + 14025025 = 44784^2 + 3745^2 .

It is a cyclic number.

It is not a de Polignac number, because 2019631681 - 2⁹ = 2019631169 is a prime.

It is a super-2 number, since 2×2019631681² = 8157824253797771522, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 2019631681.

It is not a weakly prime, because it can be changed into another prime (2019631661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1009815840 + 1009815841.

It is an arithmetic number, because the mean of its divisors is an integer number (1009815841).

Almost surely, 2^2019631681 is an apocalyptic number.

It is an amenable number.

2019631681 is a deficient number, since it is larger than the sum of its proper divisors (1).

2019631681 is an equidigital number, since it uses as much as digits as its factorization.

2019631681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15552, while the sum is 37.

The square root of 2019631681 is about 44940.3124265953. The cubic root of 2019631681 is about 1264.0300294049.

The spelling of 2019631681 in words is "two billion, nineteen million, six hundred thirty-one thousand, six hundred eighty-one".