1861310881 has 4 divisors (see below), whose sum is σ = 1866644500. Its totient is φ = 1855977264.

The previous prime is 1861310861. The next prime is 1861310887. The reversal of 1861310881 is 1880131681.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 716097600 + 1145213281 = 26760^2 + 33841^2 .

It is a cyclic number.

It is not a de Polignac number, because 1861310881 - 2⁷ = 1861310753 is a prime.

It is a super-2 number, since 2×1861310881² = 6928956391457992322, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1861310881.

It is not an unprimeable number, because it can be changed into a prime (1861310887) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2666286 + ... + 2666983.

It is an arithmetic number, because the mean of its divisors is an integer number (466661125).

Almost surely, 2^1861310881 is an apocalyptic number.

It is an amenable number.

1861310881 is a deficient number, since it is larger than the sum of its proper divisors (5333619).

1861310881 is an equidigital number, since it uses as much as digits as its factorization.

1861310881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5333618.

The product of its (nonzero) digits is 9216, while the sum is 37.

The square root of 1861310881 is about 43142.9122915920. The cubic root of 1861310881 is about 1230.0977913744.

The spelling of 1861310881 in words is "one billion, eight hundred sixty-one million, three hundred ten thousand, eight hundred eighty-one".