1991605410 has 48 divisors (see below), whose sum is σ = 5208146424. Its totient is φ = 528020736.

The previous prime is 1991605361. The next prime is 1991605487. The reversal of 1991605410 is 145061991.

1991605410 is a `hidden beast` number, since 1 + 9 + 9 + 1 + 605 + 41 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 1903489641 + 88115769 = 43629^2 + 9387^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 48387 + ... + 79526.

Almost surely, 2^1991605410 is an apocalyptic number.

1991605410 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1991605410 is an abundant number, since it is smaller than the sum of its proper divisors (3216541014).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1991605410 is a wasteful number, since it uses less digits than its factorization.

1991605410 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128099 (or 128096 counting only the distinct ones).

The product of its (nonzero) digits is 9720, while the sum is 36.

The square root of 1991605410 is about 44627.4064897345. The cubic root of 1991605410 is about 1258.1558244214.

The spelling of 1991605410 in words is "one billion, nine hundred ninety-one million, six hundred five thousand, four hundred ten".