1439423981 has 2 divisors, whose sum is σ = 1439423982. Its totient is φ = 1439423980.

The previous prime is 1439423977. The next prime is 1439423989. The reversal of 1439423981 is 1893249341.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1131245956 + 308178025 = 33634^2 + 17555^2 .

It is a cyclic number.

It is not a de Polignac number, because 1439423981 - 2² = 1439423977 is a prime.

It is a super-2 number, since 2×1439423981² = 4143882794155776722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1439423989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 719711990 + 719711991.

It is an arithmetic number, because the mean of its divisors is an integer number (719711991).

Almost surely, 2^1439423981 is an apocalyptic number.

It is an amenable number.

1439423981 is a deficient number, since it is larger than the sum of its proper divisors (1).

1439423981 is an equidigital number, since it uses as much as digits as its factorization.

1439423981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 186624, while the sum is 44.

The square root of 1439423981 is about 37939.7414461406. The cubic root of 1439423981 is about 1129.0926438448.

The spelling of 1439423981 in words is "one billion, four hundred thirty-nine million, four hundred twenty-three thousand, nine hundred eighty-one".