872216421 has 4 divisors (see below), whose sum is σ = 1162955232. Its totient is φ = 581477612.

The previous prime is 872216417. The next prime is 872216431. The reversal of 872216421 is 124612278.

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 872216421 - 2² = 872216417 is a prime.

It is a super-2 number, since 2×872216421² = 1521522970124098482, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (872216431) 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, 145369401 + ... + 145369406.

It is an arithmetic number, because the mean of its divisors is an integer number (290738808).

Almost surely, 2^872216421 is an apocalyptic number.

It is an amenable number.

872216421 is a deficient number, since it is larger than the sum of its proper divisors (290738811).

872216421 is a wasteful number, since it uses less digits than its factorization.

872216421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 290738810.

The product of its digits is 10752, while the sum is 33.

The square root of 872216421 is about 29533.3103630460. The cubic root of 872216421 is about 955.4502672832.

Adding to 872216421 its reverse (124612278), we get a palindrome (996828699).

The spelling of 872216421 in words is "eight hundred seventy-two million, two hundred sixteen thousand, four hundred twenty-one".