1821801817 has 8 divisors (see below), whose sum is σ = 1997409600. Its totient is φ = 1647858960.

The previous prime is 1821801809. The next prime is 1821801841. The reversal of 1821801817 is 7181081281.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1821801817 - 2³ = 1821801809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1821801217) 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, 413938 + ... + 418315.

It is an arithmetic number, because the mean of its divisors is an integer number (249676200).

Almost surely, 2^1821801817 is an apocalyptic number.

It is an amenable number.

1821801817 is a deficient number, since it is larger than the sum of its proper divisors (175607783).

1821801817 is a wasteful number, since it uses less digits than its factorization.

1821801817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 832463.

The product of its (nonzero) digits is 7168, while the sum is 37.

The square root of 1821801817 is about 42682.5704122889. The cubic root of 1821801817 is about 1221.3319272790.

The spelling of 1821801817 in words is "one billion, eight hundred twenty-one million, eight hundred one thousand, eight hundred seventeen".