216423421 has 4 divisors (see below), whose sum is σ = 218003292. Its totient is φ = 214843552.

The previous prime is 216423409. The next prime is 216423439. The reversal of 216423421 is 124324612.

It is a happy number.

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 162562500 + 53860921 = 12750^2 + 7339^2 .

It is a cyclic number.

It is not a de Polignac number, because 216423421 - 2⁷ = 216423293 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 (216423451) 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, 789730 + ... + 790003.

It is an arithmetic number, because the mean of its divisors is an integer number (54500823).

Almost surely, 2^216423421 is an apocalyptic number.

It is an amenable number.

216423421 is a deficient number, since it is larger than the sum of its proper divisors (1579871).

216423421 is a wasteful number, since it uses less digits than its factorization.

216423421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1579870.

The product of its digits is 2304, while the sum is 25.

The square root of 216423421 is about 14711.3364790559. The cubic root of 216423421 is about 600.3918005796.

The spelling of 216423421 in words is "two hundred sixteen million, four hundred twenty-three thousand, four hundred twenty-one".