1009857491 has 2 divisors, whose sum is σ = 1009857492. Its totient is φ = 1009857490.

The previous prime is 1009857479. The next prime is 1009857509. The reversal of 1009857491 is 1947589001.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1009857491 - 2⁶ = 1009857427 is a prime.

It is not a weakly prime, because it can be changed into another prime (1009857421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 504928745 + 504928746.

It is an arithmetic number, because the mean of its divisors is an integer number (504928746).

Almost surely, 2^1009857491 is an apocalyptic number.

1009857491 is a deficient number, since it is larger than the sum of its proper divisors (1).

1009857491 is an equidigital number, since it uses as much as digits as its factorization.

1009857491 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 90720, while the sum is 44.

The square root of 1009857491 is about 31778.2550024384. The cubic root of 1009857491 is about 1003.2750923934.

The spelling of 1009857491 in words is "one billion, nine million, eight hundred fifty-seven thousand, four hundred ninety-one".