455216721 has 4 divisors (see below), whose sum is σ = 606955632. Its totient is φ = 303477812.

The previous prime is 455216689. The next prime is 455216731. The reversal of 455216721 is 127612554.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 455216721 - 2⁵ = 455216689 is a prime.

It is not an unprimeable number, because it can be changed into a prime (455216731) 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, 75869451 + ... + 75869456.

It is an arithmetic number, because the mean of its divisors is an integer number (151738908).

Almost surely, 2^455216721 is an apocalyptic number.

It is an amenable number.

455216721 is a deficient number, since it is larger than the sum of its proper divisors (151738911).

455216721 is a wasteful number, since it uses less digits than its factorization.

455216721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151738910.

The product of its digits is 16800, while the sum is 33.

The square root of 455216721 is about 21335.8084215246. The cubic root of 455216721 is about 769.2592645949.

The spelling of 455216721 in words is "four hundred fifty-five million, two hundred sixteen thousand, seven hundred twenty-one".