221645712 has 80 divisors (see below), whose sum is σ = 584337600. Its totient is φ = 72384000.

The previous prime is 221645623. The next prime is 221645717. The reversal of 221645712 is 217546122.

It is a self number, because there is not a number n which added to its sum of digits gives 221645712.

It is not an unprimeable number, because it can be changed into a prime (221645717) 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, 634914 + ... + 635262.

It is an arithmetic number, because the mean of its divisors is an integer number (7304220).

Almost surely, 2^221645712 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 221645712, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (292168800).

221645712 is an abundant number, since it is smaller than the sum of its proper divisors (362691888).

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

221645712 is a wasteful number, since it uses less digits than its factorization.

221645712 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 592 (or 586 counting only the distinct ones).

The product of its digits is 6720, while the sum is 30.

The square root of 221645712 is about 14887.7705516978. The cubic root of 221645712 is about 605.1826163659.

The spelling of 221645712 in words is "two hundred twenty-one million, six hundred forty-five thousand, seven hundred twelve".