1815893697601 has 9 divisors (see below), whose sum is σ = 1846234033059. Its totient is φ = 1786044095400.

The previous prime is 1815893697599. The next prime is 1815893697619. The reversal of 1815893697601 is 1067963985181.

The square root of 1815893697601 is 1347551.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 59049486001 + 1756844211600 = 243001^2 + 1325460^2 .

It is not a de Polignac number, because 1815893697601 - 2¹ = 1815893697599 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1815893697001) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 82189566 + ... + 82211656.

Almost surely, 2^{1815893697601} is an apocalyptic number.

1815893697601 is the 1347551-st square number.

1815893697601 is the 673776-th centered octagonal number.

It is an amenable number.

1815893697601 is a deficient number, since it is larger than the sum of its proper divisors (30340335458).

1815893697601 is an frugal number, since it uses more digits than its factorization.

1815893697601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44304 (or 22152 counting only the distinct ones).

The product of its (nonzero) digits is 19595520, while the sum is 64.

Multiplying 1815893697601 by its sum of digits (64), we get a square (116217196646464 = 10780408²).

The spelling of 1815893697601 in words is "one trillion, eight hundred fifteen billion, eight hundred ninety-three million, six hundred ninety-seven thousand, six hundred one".