1821516206401 has 8 divisors (see below), whose sum is σ = 1884915506880. Its totient is φ = 1758156132432.

The previous prime is 1821516206369. The next prime is 1821516206407. The reversal of 1821516206401 is 1046026151281.

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

It is a cyclic number.

It is not a de Polignac number, because 1821516206401 - 2⁵ = 1821516206369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1821516206407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9712125 + ... + 9897898.

It is an arithmetic number, because the mean of its divisors is an integer number (235614438360).

Almost surely, 2^{1821516206401} is an apocalyptic number.

It is an amenable number.

1821516206401 is a deficient number, since it is larger than the sum of its proper divisors (63399300479).

1821516206401 is a wasteful number, since it uses less digits than its factorization.

1821516206401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19613255.

The product of its (nonzero) digits is 23040, while the sum is 37.

The spelling of 1821516206401 in words is "one trillion, eight hundred twenty-one billion, five hundred sixteen million, two hundred six thousand, four hundred one".