1991570799 has 4 divisors (see below), whose sum is σ = 2655427736. Its totient is φ = 1327713864.

The previous prime is 1991570797. The next prime is 1991570813. The reversal of 1991570799 is 9970751991.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 1991570799 - 2¹ = 1991570797 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1991570797) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 331928464 + ... + 331928469.

It is an arithmetic number, because the mean of its divisors is an integer number (663856934).

Almost surely, 2^1991570799 is an apocalyptic number.

1991570799 is a deficient number, since it is larger than the sum of its proper divisors (663856937).

1991570799 is an equidigital number, since it uses as much as digits as its factorization.

1991570799 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 663856936.

The product of its (nonzero) digits is 1607445, while the sum is 57.

The square root of 1991570799 is about 44627.0187106421. The cubic root of 1991570799 is about 1258.1485361163.

The spelling of 1991570799 in words is "one billion, nine hundred ninety-one million, five hundred seventy thousand, seven hundred ninety-nine".