1611881 has 2 divisors, whose sum is σ = 1611882. Its totient is φ = 1611880.

The previous prime is 1611877. The next prime is 1611899. The reversal of 1611881 is 1881161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1478656 + 133225 = 1216^2 + 365^2 .

It is an emirp because it is prime and its reverse (1881161) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1611881 - 2² = 1611877 is a prime.

It is a super-2 number, since 2×1611881² = 5196320716322, which contains 22 as substring.

It is equal to p₁₂₁₉₈₅ and since 1611881 and 121985 have the same sum of digits, it is a Honaker prime.

It is a plaindrome in base 13.

It is a self number, because there is not a number n which added to its sum of digits gives 1611881.

It is not a weakly prime, because it can be changed into another prime (1611851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 805940 + 805941.

It is an arithmetic number, because the mean of its divisors is an integer number (805941).

2^1611881 is an apocalyptic number.

It is an amenable number.

1611881 is a deficient number, since it is larger than the sum of its proper divisors (1).

1611881 is an equidigital number, since it uses as much as digits as its factorization.

1611881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 384, while the sum is 26.

The square root of 1611881 is about 1269.5987555129. The cubic root of 1611881 is about 117.2494980149.

It can be divided in two parts, 16 and 11881, that multiplied together give a square (190096 = 436²).

The spelling of 1611881 in words is "one million, six hundred eleven thousand, eight hundred eighty-one".