1051991491 has 2 divisors, whose sum is σ = 1051991492. Its totient is φ = 1051991490.

The previous prime is 1051991461. The next prime is 1051991497. The reversal of 1051991491 is 1941991501.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1051991491 - 2²⁵ = 1018437059 is a prime.

It is a super-2 number, since 2×1051991491² = 2213372194272806162, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1051991497) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 525995745 + 525995746.

It is an arithmetic number, because the mean of its divisors is an integer number (525995746).

Almost surely, 2^1051991491 is an apocalyptic number.

1051991491 is a deficient number, since it is larger than the sum of its proper divisors (1).

1051991491 is an equidigital number, since it uses as much as digits as its factorization.

1051991491 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 14580, while the sum is 40.

The square root of 1051991491 is about 32434.4183083341. The cubic root of 1051991491 is about 1017.0385364468.

The spelling of 1051991491 in words is "one billion, fifty-one million, nine hundred ninety-one thousand, four hundred ninety-one".