216461251 has 4 divisors (see below), whose sum is σ = 223443904. Its totient is φ = 209478600.

The previous prime is 216461239. The next prime is 216461291. The reversal of 216461251 is 152164612.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216461251 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216461291) 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, 3491280 + ... + 3491341.

It is an arithmetic number, because the mean of its divisors is an integer number (55860976).

Almost surely, 2^216461251 is an apocalyptic number.

216461251 is a deficient number, since it is larger than the sum of its proper divisors (6982653).

216461251 is an equidigital number, since it uses as much as digits as its factorization.

216461251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6982652.

The product of its digits is 2880, while the sum is 28.

The square root of 216461251 is about 14712.6221660179. The cubic root of 216461251 is about 600.4267806178.

The spelling of 216461251 in words is "two hundred sixteen million, four hundred sixty-one thousand, two hundred fifty-one".