1234987981 has 2 divisors, whose sum is σ = 1234987982. Its totient is φ = 1234987980.

The previous prime is 1234987931. The next prime is 1234988003. The reversal of 1234987981 is 1897894321.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1173679081 + 61308900 = 34259^2 + 7830^2 .

It is an emirp because it is prime and its reverse (1897894321) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1234987981 - 2¹¹ = 1234985933 is a prime.

It is a super-2 number, since 2×1234987981² = 3050390626428912722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1234987931) 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, 617493990 + 617493991.

It is an arithmetic number, because the mean of its divisors is an integer number (617493991).

Almost surely, 2^1234987981 is an apocalyptic number.

It is an amenable number.

1234987981 is a deficient number, since it is larger than the sum of its proper divisors (1).

1234987981 is an equidigital number, since it uses as much as digits as its factorization.

1234987981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 870912, while the sum is 52.

The square root of 1234987981 is about 35142.3957777497. The cubic root of 1234987981 is about 1072.8876438635.

The spelling of 1234987981 in words is "one billion, two hundred thirty-four million, nine hundred eighty-seven thousand, nine hundred eighty-one".