221040442100 has 72 divisors (see below), whose sum is σ = 483539494200. Its totient is φ = 87702289920.

The previous prime is 221040442093. The next prime is 221040442123. The reversal of 221040442100 is 1244040122.

It can be written as a sum of positive squares in 12 ways, for example, as 102997348624 + 118043093476 = 320932^2 + 343574^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 11269502 + ... + 11289098.

Almost surely, 2^221040442100 is an apocalyptic number.

221040442100 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 221040442100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (241769747100).

221040442100 is an abundant number, since it is smaller than the sum of its proper divisors (262499052100).

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

221040442100 is a wasteful number, since it uses less digits than its factorization.

221040442100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20517 (or 20510 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 20.

Adding to 221040442100 its reverse (1244040122), we get a palindrome (222284482222).

The spelling of 221040442100 in words is "two hundred twenty-one billion, forty million, four hundred forty-two thousand, one hundred".