1815945805897 has 16 divisors (see below), whose sum is σ = 1889800274880. Its totient is φ = 1742860929600.

The previous prime is 1815945805859. The next prime is 1815945805913. The reversal of 1815945805897 is 7985085495181.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 1815945805897 - 2¹⁵ = 1815945773129 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1815945805847) 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, 4779543 + ... + 5145475.

It is an arithmetic number, because the mean of its divisors is an integer number (118112517180).

Almost surely, 2^{1815945805897} is an apocalyptic number.

It is an amenable number.

1815945805897 is a deficient number, since it is larger than the sum of its proper divisors (73854468983).

1815945805897 is a wasteful number, since it uses less digits than its factorization.

1815945805897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 366984.

The product of its (nonzero) digits is 145152000, while the sum is 70.

The spelling of 1815945805897 in words is "one trillion, eight hundred fifteen billion, nine hundred forty-five million, eight hundred five thousand, eight hundred ninety-seven".