990043771 has 2 divisors, whose sum is σ = 990043772. Its totient is φ = 990043770.

The previous prime is 990043759. The next prime is 990043781. The reversal of 990043771 is 177340099.

It is a strong prime.

It is an emirp because it is prime and its reverse (177340099) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 990043771 - 2⁷ = 990043643 is a prime.

It is not a weakly prime, because it can be changed into another prime (990043711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495021885 + 495021886.

It is an arithmetic number, because the mean of its divisors is an integer number (495021886).

Almost surely, 2^990043771 is an apocalyptic number.

990043771 is a deficient number, since it is larger than the sum of its proper divisors (1).

990043771 is an equidigital number, since it uses as much as digits as its factorization.

990043771 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 47628, while the sum is 40.

The square root of 990043771 is about 31464.9610042663. The cubic root of 990043771 is about 996.6701816162.

The spelling of 990043771 in words is "nine hundred ninety million, forty-three thousand, seven hundred seventy-one".