1859778961 has 4 divisors (see below), whose sum is σ = 1923909300. Its totient is φ = 1795648624.

The previous prime is 1859778959. The next prime is 1859779007. The reversal of 1859778961 is 1698779581.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1698779581 = 79 ⋅21503539.

It can be written as a sum of positive squares in 2 ways, for example, as 413878336 + 1445900625 = 20344^2 + 38025^2 .

It is a cyclic number.

It is not a de Polignac number, because 1859778961 - 2¹ = 1859778959 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1859778961.

It is not an unprimeable number, because it can be changed into a prime (1859778911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32065126 + ... + 32065183.

It is an arithmetic number, because the mean of its divisors is an integer number (480977325).

Almost surely, 2^1859778961 is an apocalyptic number.

It is an amenable number.

1859778961 is a deficient number, since it is larger than the sum of its proper divisors (64130339).

1859778961 is an equidigital number, since it uses as much as digits as its factorization.

1859778961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64130338.

The product of its digits is 7620480, while the sum is 61.

The square root of 1859778961 is about 43125.1546200127. The cubic root of 1859778961 is about 1229.7602284518.

The spelling of 1859778961 in words is "one billion, eight hundred fifty-nine million, seven hundred seventy-eight thousand, nine hundred sixty-one".