1398763981 has 2 divisors, whose sum is σ = 1398763982. Its totient is φ = 1398763980.

The previous prime is 1398763957. The next prime is 1398763997. The reversal of 1398763981 is 1893678931.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1014995881 + 383768100 = 31859^2 + 19590^2 .

It is a cyclic number.

It is not a de Polignac number, because 1398763981 - 2¹³ = 1398755789 is a prime.

It is a super-2 number, since 2×1398763981² = 3913081349085936722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1398763921) 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, 699381990 + 699381991.

It is an arithmetic number, because the mean of its divisors is an integer number (699381991).

Almost surely, 2^1398763981 is an apocalyptic number.

It is an amenable number.

1398763981 is a deficient number, since it is larger than the sum of its proper divisors (1).

1398763981 is an equidigital number, since it uses as much as digits as its factorization.

1398763981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1959552, while the sum is 55.

The square root of 1398763981 is about 37400.0532218873. The cubic root of 1398763981 is about 1118.3596259127.

The spelling of 1398763981 in words is "one billion, three hundred ninety-eight million, seven hundred sixty-three thousand, nine hundred eighty-one".