216423251 has 4 divisors (see below), whose sum is σ = 236098104. Its totient is φ = 196748400.

The previous prime is 216423227. The next prime is 216423271. The reversal of 216423251 is 152324612.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 216423251 - 2⁶ = 216423187 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 216423251.

It is not an unprimeable number, because it can be changed into a prime (216423271) 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, 9837410 + ... + 9837431.

It is an arithmetic number, because the mean of its divisors is an integer number (59024526).

Almost surely, 2^216423251 is an apocalyptic number.

216423251 is a deficient number, since it is larger than the sum of its proper divisors (19674853).

216423251 is a wasteful number, since it uses less digits than its factorization.

216423251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19674852.

The product of its digits is 2880, while the sum is 26.

The square root of 216423251 is about 14711.3307011976. The cubic root of 216423251 is about 600.3916433776.

Adding to 216423251 its reverse (152324612), we get a palindrome (368747863).

The spelling of 216423251 in words is "two hundred sixteen million, four hundred twenty-three thousand, two hundred fifty-one".