1812661 has 2 divisors, whose sum is σ = 1812662. Its totient is φ = 1812660.

The previous prime is 1812623. The next prime is 1812673. The reversal of 1812661 is 1662181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1739761 + 72900 = 1319^2 + 270^2 .

It is a cyclic number.

It is not a de Polignac number, because 1812661 - 2¹³ = 1804469 is a prime.

1812661 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1812611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 906330 + 906331.

It is an arithmetic number, because the mean of its divisors is an integer number (906331).

2^1812661 is an apocalyptic number.

It is an amenable number.

1812661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1812661 is an equidigital number, since it uses as much as digits as its factorization.

1812661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 576, while the sum is 25.

The square root of 1812661 is about 1346.3509943547. The cubic root of 1812661 is about 121.9285840203.

The spelling of 1812661 in words is "one million, eight hundred twelve thousand, six hundred sixty-one".