72221217 has 16 divisors (see below), whose sum is σ = 97861632. Its totient is φ = 47370960.

The previous prime is 72221197. The next prime is 72221239. The reversal of 72221217 is 71212227.

It is not a de Polignac number, because 72221217 - 2⁶ = 72221153 is a prime.

It is a super-2 number, since 2×72221217² = 10431808369922178, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (72221257) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 49188 + ... + 50634.

It is an arithmetic number, because the mean of its divisors is an integer number (6116352).

Almost surely, 2^72221217 is an apocalyptic number.

It is an amenable number.

72221217 is a deficient number, since it is larger than the sum of its proper divisors (25640415).

72221217 is a wasteful number, since it uses less digits than its factorization.

72221217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1708.

The product of its digits is 784, while the sum is 24.

The square root of 72221217 is about 8498.3067136930. The cubic root of 72221217 is about 416.4423937234.

The spelling of 72221217 in words is "seventy-two million, two hundred twenty-one thousand, two hundred seventeen".