1820201909091 has 16 divisors (see below), whose sum is σ = 2509633511424. Its totient is φ = 1172802574944.

The previous prime is 1820201909087. The next prime is 1820201909107. The reversal of 1820201909091 is 1909091020281.

It is not a de Polignac number, because 1820201909091 - 2² = 1820201909087 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1820201909021) 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, 85420771 + ... + 85442076.

It is an arithmetic number, because the mean of its divisors is an integer number (156852094464).

Almost surely, 2^{1820201909091} is an apocalyptic number.

1820201909091 is a deficient number, since it is larger than the sum of its proper divisors (689431602333).

1820201909091 is a wasteful number, since it uses less digits than its factorization.

1820201909091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 170862970.

The product of its (nonzero) digits is 23328, while the sum is 42.

The spelling of 1820201909091 in words is "one trillion, eight hundred twenty billion, two hundred one million, nine hundred nine thousand, ninety-one".