221978880 has 180 divisors, whose sum is σ = 794652012. Its totient is φ = 59166720.

The previous prime is 221978831. The next prime is 221978899. The reversal of 221978880 is 88879122.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 156950784 + 65028096 = 12528^2 + 8064^2 .

It is a tau number, because it is divible by the number of its divisors (180).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 102610 + ... + 104750.

Almost surely, 2^221978880 is an apocalyptic number.

221978880 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 221978880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (397326006).

221978880 is an abundant number, since it is smaller than the sum of its proper divisors (572673132).

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

221978880 is an equidigital number, since it uses as much as digits as its factorization.

221978880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2174 (or 2151 counting only the distinct ones).

The product of its (nonzero) digits is 129024, while the sum is 45.

The square root of 221978880 is about 14898.9556680997. The cubic root of 221978880 is about 605.4856924455.

The spelling of 221978880 in words is "two hundred twenty-one million, nine hundred seventy-eight thousand, eight hundred eighty".