1991570798 has 24 divisors (see below), whose sum is σ = 3486244032. Its totient is φ = 850790304.

The previous prime is 1991570797. The next prime is 1991570813. The reversal of 1991570798 is 8970751991.

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 11 ways as a sum of consecutive naturals, for example, 1790 + ... + 63137.

It is an arithmetic number, because the mean of its divisors is an integer number (145260168).

Almost surely, 2^1991570798 is an apocalyptic number.

1991570798 is a deficient number, since it is larger than the sum of its proper divisors (1494673234).

1991570798 is a wasteful number, since it uses less digits than its factorization.

1991570798 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65256 (or 65249 counting only the distinct ones).

The product of its (nonzero) digits is 1428840, while the sum is 56.

The square root of 1991570798 is about 44627.0186994381. The cubic root of 1991570798 is about 1258.1485359057.

The spelling of 1991570798 in words is "one billion, nine hundred ninety-one million, five hundred seventy thousand, seven hundred ninety-eight".