216949451 has 4 divisors (see below), whose sum is σ = 218085504. Its totient is φ = 215813400.

The previous prime is 216949423. The next prime is 216949457. The reversal of 216949451 is 154949612.

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 216949451 - 2¹⁸ = 216687307 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 216949399 and 216949408.

It is not an unprimeable number, because it can be changed into a prime (216949457) 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, 567740 + ... + 568121.

It is an arithmetic number, because the mean of its divisors is an integer number (54521376).

Almost surely, 2^216949451 is an apocalyptic number.

216949451 is a deficient number, since it is larger than the sum of its proper divisors (1136053).

216949451 is a wasteful number, since it uses less digits than its factorization.

216949451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1136052.

The product of its digits is 77760, while the sum is 41.

The square root of 216949451 is about 14729.2040178687. The cubic root of 216949451 is about 600.8778363422.

The spelling of 216949451 in words is "two hundred sixteen million, nine hundred forty-nine thousand, four hundred fifty-one".