1801213620649 has 3 divisors (see below), whose sum is σ = 1801214962743. Its totient is φ = 1801212278556.

The previous prime is 1801213620641. The next prime is 1801213620691. The reversal of 1801213620649 is 9460263121081.

The square root of 1801213620649 is 1342093.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 63910368025 + 1737303252624 = 252805^2 + 1318068^2 .

It is not a de Polignac number, because 1801213620649 - 2³ = 1801213620641 is a prime.

It is a super-2 number, since 2×1801213620649² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1801213620641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 671047 + ... + 2013139.

It is an arithmetic number, because the mean of its divisors is an integer number (600404987581).

Almost surely, 2^{1801213620649} is an apocalyptic number.

1801213620649 is the 1342093-rd square number.

1801213620649 is the 671047-th centered octagonal number.

It is an amenable number.

1801213620649 is a deficient number, since it is larger than the sum of its proper divisors (1342094).

1801213620649 is an frugal number, since it uses more digits than its factorization.

1801213620649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2684186 (or 1342093 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 43.

The spelling of 1801213620649 in words is "one trillion, eight hundred one billion, two hundred thirteen million, six hundred twenty thousand, six hundred forty-nine".