1540001891 has 2 divisors, whose sum is σ = 1540001892. Its totient is φ = 1540001890.

The previous prime is 1540001863. The next prime is 1540001909. The reversal of 1540001891 is 1981000451.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1540001891 - 2¹⁰ = 1540000867 is a prime.

It is not a weakly prime, because it can be changed into another prime (1540001821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 770000945 + 770000946.

It is an arithmetic number, because the mean of its divisors is an integer number (770000946).

Almost surely, 2^1540001891 is an apocalyptic number.

1540001891 is a deficient number, since it is larger than the sum of its proper divisors (1).

1540001891 is an equidigital number, since it uses as much as digits as its factorization.

1540001891 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1440, while the sum is 29.

The square root of 1540001891 is about 39242.8578342607. The cubic root of 1540001891 is about 1154.8008229596.

Subtracting from 1540001891 its product of nonzero digits (1440), we obtain a palindrome (1540000451).

The spelling of 1540001891 in words is "one billion, five hundred forty million, one thousand, eight hundred ninety-one".