8420861 has 4 divisors (see below), whose sum is σ = 8507772. Its totient is φ = 8333952.

The previous prime is 8420843. The next prime is 8420869. The reversal of 8420861 is 1680248.

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 4923961 + 3496900 = 2219^2 + 1870^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8420861 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8420869) 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, 43310 + ... + 43503.

It is an arithmetic number, because the mean of its divisors is an integer number (2126943).

Almost surely, 2^8420861 is an apocalyptic number.

It is an amenable number.

8420861 is a deficient number, since it is larger than the sum of its proper divisors (86911).

8420861 is an equidigital number, since it uses as much as digits as its factorization.

8420861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86910.

The product of its (nonzero) digits is 3072, while the sum is 29.

The square root of 8420861 is about 2901.8719820144. The cubic root of 8420861 is about 203.4474103814.

The spelling of 8420861 in words is "eight million, four hundred twenty thousand, eight hundred sixty-one".