1820669 has 2 divisors, whose sum is σ = 1820670. Its totient is φ = 1820668.

The previous prime is 1820647. The next prime is 1820671. The reversal of 1820669 is 9660281.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1295044 + 525625 = 1138^2 + 725^2 .

It is a cyclic number.

It is not a de Polignac number, because 1820669 - 2¹⁶ = 1755133 is a prime.

It is a super-2 number, since 2×1820669² = 6629671215122, which contains 22 as substring.

Together with 1820671, it forms a pair of twin primes.

It is a Chen prime.

It is an Ulam number.

It is equal to p₁₃₆₄₉₉ and since 1820669 and 136499 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1820629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 910334 + 910335.

It is an arithmetic number, because the mean of its divisors is an integer number (910335).

2^1820669 is an apocalyptic number.

It is an amenable number.

1820669 is a deficient number, since it is larger than the sum of its proper divisors (1).

1820669 is an equidigital number, since it uses as much as digits as its factorization.

1820669 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 32.

The square root of 1820669 is about 1349.3216814385. The cubic root of 1820669 is about 122.1078728784.

It can be divided in two parts, 1820 and 669, that multiplied together give a triangular number (1217580 = T₁₅₆₀).

The spelling of 1820669 in words is "one million, eight hundred twenty thousand, six hundred sixty-nine".