84123421 has 4 divisors (see below), whose sum is σ = 84156732. Its totient is φ = 84090112.

The previous prime is 84123419. The next prime is 84123449. The reversal of 84123421 is 12432148.

84123421 = 6485² + 6486².

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 42068196 + 42055225 = 6486^2 + 6485^2 .

It is a cyclic number.

It is not a de Polignac number, because 84123421 - 2¹ = 84123419 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 (84121421) 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, 12526 + ... + 18031.

It is an arithmetic number, because the mean of its divisors is an integer number (21039183).

Almost surely, 2^84123421 is an apocalyptic number.

84123421 is the 6486-th centered square number.

It is an amenable number.

84123421 is a deficient number, since it is larger than the sum of its proper divisors (33311).

84123421 is a wasteful number, since it uses less digits than its factorization.

84123421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33310.

The product of its digits is 1536, while the sum is 25.

The square root of 84123421 is about 9171.8820860279. The cubic root of 84123421 is about 438.1663029242.

Adding to 84123421 its reverse (12432148), we get a palindrome (96555569).

The spelling of 84123421 in words is "eighty-four million, one hundred twenty-three thousand, four hundred twenty-one".