861473821 has 4 divisors (see below), whose sum is σ = 927741052. Its totient is φ = 795206592.

The previous prime is 861473807. The next prime is 861473843. The reversal of 861473821 is 128374168.

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 77193796 + 784280025 = 8786^2 + 28005^2 .

It is a cyclic number.

It is not a de Polignac number, because 861473821 - 2¹⁹ = 860949533 is a prime.

It is a super-3 number, since 3×861473821³ (a number of 28 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861473881) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33133596 + ... + 33133621.

It is an arithmetic number, because the mean of its divisors is an integer number (231935263).

Almost surely, 2^861473821 is an apocalyptic number.

It is an amenable number.

861473821 is a deficient number, since it is larger than the sum of its proper divisors (66267231).

861473821 is a wasteful number, since it uses less digits than its factorization.

861473821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66267230.

The product of its digits is 64512, while the sum is 40.

The square root of 861473821 is about 29350.8742799938. The cubic root of 861473821 is about 951.5114705812.

The spelling of 861473821 in words is "eight hundred sixty-one million, four hundred seventy-three thousand, eight hundred twenty-one".