1813561 has 2 divisors, whose sum is σ = 1813562. Its totient is φ = 1813560.

The previous prime is 1813547. The next prime is 1813579. The reversal of 1813561 is 1653181.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1806336 + 7225 = 1344^2 + 85^2 .

It is an emirp because it is prime and its reverse (1653181) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1813561 - 2¹³ = 1805369 is a prime.

It is a super-3 number, since 3×1813561³ = 17894425433313232443, which contains 333 as substring.

It is an Ulam number.

It is a pancake number, because a pancake can be divided into 1813561 parts by 1904 straight cuts.

It is not a weakly prime, because it can be changed into another prime (1813961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 906780 + 906781.

It is an arithmetic number, because the mean of its divisors is an integer number (906781).

2^1813561 is an apocalyptic number.

It is an amenable number.

1813561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1813561 is an equidigital number, since it uses as much as digits as its factorization.

1813561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 720, while the sum is 25.

The square root of 1813561 is about 1346.6851896416. The cubic root of 1813561 is about 121.9487601719.

The spelling of 1813561 in words is "one million, eight hundred thirteen thousand, five hundred sixty-one".