991946057 has 2 divisors, whose sum is σ = 991946058. Its totient is φ = 991946056.

The previous prime is 991946003. The next prime is 991946063. The reversal of 991946057 is 750649199.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 914699536 + 77246521 = 30244^2 + 8789^2 .

It is a cyclic number.

It is not a de Polignac number, because 991946057 - 2¹² = 991941961 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 991945996 and 991946014.

It is not a weakly prime, because it can be changed into another prime (991946077) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495973028 + 495973029.

It is an arithmetic number, because the mean of its divisors is an integer number (495973029).

Almost surely, 2^991946057 is an apocalyptic number.

It is an amenable number.

991946057 is a deficient number, since it is larger than the sum of its proper divisors (1).

991946057 is an equidigital number, since it uses as much as digits as its factorization.

991946057 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 612360, while the sum is 50.

The square root of 991946057 is about 31495.1751384240. The cubic root of 991946057 is about 997.3081125775.

The spelling of 991946057 in words is "nine hundred ninety-one million, nine hundred forty-six thousand, fifty-seven".