999456781 has 2 divisors, whose sum is σ = 999456782. Its totient is φ = 999456780.

The previous prime is 999456767. The next prime is 999456803. The reversal of 999456781 is 187654999.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 951722500 + 47734281 = 30850^2 + 6909^2 .

It is a cyclic number.

It is not a de Polignac number, because 999456781 - 2⁵ = 999456749 is a prime.

It is a super-2 number, since 2×999456781² = 1997827714173763922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (999456721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499728390 + 499728391.

It is an arithmetic number, because the mean of its divisors is an integer number (499728391).

Almost surely, 2^999456781 is an apocalyptic number.

It is an amenable number.

999456781 is a deficient number, since it is larger than the sum of its proper divisors (1).

999456781 is an equidigital number, since it uses as much as digits as its factorization.

999456781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4898880, while the sum is 58.

The square root of 999456781 is about 31614.1863883922. The cubic root of 999456781 is about 999.8188942027.

The spelling of 999456781 in words is "nine hundred ninety-nine million, four hundred fifty-six thousand, seven hundred eighty-one".