87221221 has 4 divisors (see below), whose sum is σ = 91013472. Its totient is φ = 83428972.

The previous prime is 87221207. The next prime is 87221231. The reversal of 87221221 is 12212278.

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 87221221 - 2¹¹ = 87219173 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (87221231) 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, 1896091 + ... + 1896136.

It is an arithmetic number, because the mean of its divisors is an integer number (22753368).

Almost surely, 2^87221221 is an apocalyptic number.

It is an amenable number.

87221221 is a deficient number, since it is larger than the sum of its proper divisors (3792251).

87221221 is a wasteful number, since it uses less digits than its factorization.

87221221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3792250.

The product of its digits is 896, while the sum is 25.

The square root of 87221221 is about 9339.2302145305. The cubic root of 87221221 is about 443.4800154702.

Adding to 87221221 its reverse (12212278), we get a palindrome (99433499).

The spelling of 87221221 in words is "eighty-seven million, two hundred twenty-one thousand, two hundred twenty-one".