810427861 has 4 divisors (see below), whose sum is σ = 810572224. Its totient is φ = 810283500.

The previous prime is 810427831. The next prime is 810427873. The reversal of 810427861 is 168724018.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 168724018 = 2 ⋅84362009.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-810427861 is a prime.

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 810427861.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (810427831) 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, 63405 + ... + 75106.

It is an arithmetic number, because the mean of its divisors is an integer number (202643056).

Almost surely, 2^810427861 is an apocalyptic number.

It is an amenable number.

810427861 is a deficient number, since it is larger than the sum of its proper divisors (144363).

810427861 is a wasteful number, since it uses less digits than its factorization.

810427861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 144362.

The product of its (nonzero) digits is 21504, while the sum is 37.

The square root of 810427861 is about 28468.0147007128. The cubic root of 810427861 is about 932.3338542048. Note that the first 3 decimals are identical.

The spelling of 810427861 in words is "eight hundred ten million, four hundred twenty-seven thousand, eight hundred sixty-one".