1991769625 has 8 divisors (see below), whose sum is σ = 2485728648. Its totient is φ = 1593415600.

The previous prime is 1991769599. The next prime is 1991769629. The reversal of 1991769625 is 5269671991.

It can be written as a sum of positive squares in 4 ways, for example, as 58936329 + 1932833296 = 7677^2 + 43964^2 .

It is not a de Polignac number, because 1991769625 - 2¹³ = 1991761433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1991769629) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7966954 + ... + 7967203.

It is an arithmetic number, because the mean of its divisors is an integer number (310716081).

Almost surely, 2^1991769625 is an apocalyptic number.

It is an amenable number.

1991769625 is a deficient number, since it is larger than the sum of its proper divisors (493959023).

1991769625 is an equidigital number, since it uses as much as digits as its factorization.

1991769625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15934172 (or 15934162 counting only the distinct ones).

The product of its digits is 1837080, while the sum is 55.

The square root of 1991769625 is about 44629.2462965710. The cubic root of 1991769625 is about 1258.1904032892.

The spelling of 1991769625 in words is "one billion, nine hundred ninety-one million, seven hundred sixty-nine thousand, six hundred twenty-five".