72221664 has 96 divisors (see below), whose sum is σ = 198132480. Its totient is φ = 23014400.

The previous prime is 72221647. The next prime is 72221671. The reversal of 72221664 is 46612227.

It is a tau number, because it is divible by the number of its divisors (96).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 232069 + ... + 232379.

It is an arithmetic number, because the mean of its divisors is an integer number (2063880).

Almost surely, 2^72221664 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 72221664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (99066240).

72221664 is an abundant number, since it is smaller than the sum of its proper divisors (125910816).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

72221664 is a wasteful number, since it uses less digits than its factorization.

72221664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 424 (or 416 counting only the distinct ones).

The product of its digits is 8064, while the sum is 30.

The square root of 72221664 is about 8498.3330130091. Note that the first 3 decimals coincide. The cubic root of 72221664 is about 416.4432528863.

The spelling of 72221664 in words is "seventy-two million, two hundred twenty-one thousand, six hundred sixty-four".