1381963981 has 2 divisors, whose sum is σ = 1381963982. Its totient is φ = 1381963980.

The previous prime is 1381963943. The next prime is 1381963987. The reversal of 1381963981 is 1893691831.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1363824900 + 18139081 = 36930^2 + 4259^2 .

It is a cyclic number.

It is not a de Polignac number, because 1381963981 - 2⁷ = 1381963853 is a prime.

It is a super-2 number, since 2×1381963981² = 3819648889562736722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1381963987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 690981990 + 690981991.

It is an arithmetic number, because the mean of its divisors is an integer number (690981991).

Almost surely, 2^1381963981 is an apocalyptic number.

It is an amenable number.

1381963981 is a deficient number, since it is larger than the sum of its proper divisors (1).

1381963981 is an equidigital number, since it uses as much as digits as its factorization.

1381963981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 279936, while the sum is 49.

The square root of 1381963981 is about 37174.7761392049. The cubic root of 1381963981 is about 1113.8641884852.

The spelling of 1381963981 in words is "one billion, three hundred eighty-one million, nine hundred sixty-three thousand, nine hundred eighty-one".