891424221 has 4 divisors (see below), whose sum is σ = 1188565632. Its totient is φ = 594282812.

The previous prime is 891424217. The next prime is 891424253. The reversal of 891424221 is 122424198.

891424221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 891424221 - 2² = 891424217 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (891424201) 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, 148570701 + ... + 148570706.

It is an arithmetic number, because the mean of its divisors is an integer number (297141408).

Almost surely, 2^891424221 is an apocalyptic number.

It is an amenable number.

891424221 is a deficient number, since it is larger than the sum of its proper divisors (297141411).

891424221 is a wasteful number, since it uses less digits than its factorization.

891424221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 297141410.

The product of its digits is 9216, while the sum is 33.

The square root of 891424221 is about 29856.7282366973. The cubic root of 891424221 is about 962.4129912015.

The spelling of 891424221 in words is "eight hundred ninety-one million, four hundred twenty-four thousand, two hundred twenty-one".