221729640 has 256 divisors, whose sum is σ = 790352640. Its totient is φ = 49152000.

The previous prime is 221729609. The next prime is 221729647. The reversal of 221729640 is 46927122.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (221729647) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 919920 + ... + 920160.

It is an arithmetic number, because the mean of its divisors is an integer number (3087315).

Almost surely, 2^221729640 is an apocalyptic number.

221729640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221729640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (395176320).

221729640 is an abundant number, since it is smaller than the sum of its proper divisors (568623000).

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

221729640 is a wasteful number, since it uses less digits than its factorization.

221729640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 324 (or 320 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 33.

The square root of 221729640 is about 14890.5889742481. The cubic root of 221729640 is about 605.2589925439.

The spelling of 221729640 in words is "two hundred twenty-one million, seven hundred twenty-nine thousand, six hundred forty".