991150057 has 2 divisors, whose sum is σ = 991150058. Its totient is φ = 991150056.

The previous prime is 991150049. The next prime is 991150091. The reversal of 991150057 is 750051199.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 656589376 + 334560681 = 25624^2 + 18291^2 .

It is a cyclic number.

It is not a de Polignac number, because 991150057 - 2³ = 991150049 is a prime.

It is a super-2 number, since 2×991150057² = 1964756870982206498, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 991149998 and 991150025.

It is not a weakly prime, because it can be changed into another prime (991150757) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495575028 + 495575029.

It is an arithmetic number, because the mean of its divisors is an integer number (495575029).

Almost surely, 2^991150057 is an apocalyptic number.

It is an amenable number.

991150057 is a deficient number, since it is larger than the sum of its proper divisors (1).

991150057 is an equidigital number, since it uses as much as digits as its factorization.

991150057 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 14175, while the sum is 37.

The square root of 991150057 is about 31482.5357460291. The cubic root of 991150057 is about 997.0412735715.

The spelling of 991150057 in words is "nine hundred ninety-one million, one hundred fifty thousand, fifty-seven".