87072221 has 4 divisors (see below), whose sum is σ = 87096672. Its totient is φ = 87047772.

The previous prime is 87072217. The next prime is 87072277. The reversal of 87072221 is 12227078.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12227078 = 2 ⋅6113539.

It is a cyclic number.

It is not a de Polignac number, because 87072221 - 2² = 87072217 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 (87072281) 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, 5735 + ... + 14388.

It is an arithmetic number, because the mean of its divisors is an integer number (21774168).

Almost surely, 2^87072221 is an apocalyptic number.

It is an amenable number.

87072221 is a deficient number, since it is larger than the sum of its proper divisors (24451).

87072221 is a wasteful number, since it uses less digits than its factorization.

87072221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24450.

The product of its (nonzero) digits is 3136, while the sum is 29.

The square root of 87072221 is about 9331.2497019424. The cubic root of 87072221 is about 443.2273392499.

Adding to 87072221 its reverse (12227078), we get a palindrome (99299299).

The spelling of 87072221 in words is "eighty-seven million, seventy-two thousand, two hundred twenty-one".