1810020091 has 16 divisors (see below), whose sum is σ = 2005357536. Its totient is φ = 1620000000.

The previous prime is 1810020089. The next prime is 1810020109. The reversal of 1810020091 is 1900200181.

It is a 8-Lehmer number, since φ(1810020091) divides (1810020091-1)⁸.

It is a cyclic number.

It is not a de Polignac number, because 1810020091 - 2¹ = 1810020089 is a prime.

It is a Duffinian number.

1810020091 is a modest number, since divided by 20091 gives 1810 as remainder.

It is not an unprimeable number, because it can be changed into a prime (1810020691) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 196591 + ... + 205591.

It is an arithmetic number, because the mean of its divisors is an integer number (125334846).

Almost surely, 2^1810020091 is an apocalyptic number.

1810020091 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1810020091 is a deficient number, since it is larger than the sum of its proper divisors (195337445).

1810020091 is a wasteful number, since it uses less digits than its factorization.

1810020091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9294.

The product of its (nonzero) digits is 144, while the sum is 22.

The square root of 1810020091 is about 42544.3308914361. The cubic root of 1810020091 is about 1218.6934168743.

The spelling of 1810020091 in words is "one billion, eight hundred ten million, twenty thousand, ninety-one".