221000001020 has 96 divisors (see below), whose sum is σ = 501878172096. Its totient is φ = 81433497600.

The previous prime is 221000000987. The next prime is 221000001059. The reversal of 221000001020 is 20100000122.

It is a junction number, because it is equal to n+sod(n) for n = 221000000989 and 221000001007.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7571855 + ... + 7600985.

It is an arithmetic number, because the mean of its divisors is an integer number (5227897626).

Almost surely, 2^221000001020 is an apocalyptic number.

221000001020 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 221000001020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (250939086048).

221000001020 is an abundant number, since it is smaller than the sum of its proper divisors (280878171076).

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

221000001020 is a wasteful number, since it uses less digits than its factorization.

221000001020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29631 (or 29629 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 8.

Adding to 221000001020 its reverse (20100000122), we get a palindrome (241100001142).

The spelling of 221000001020 in words is "two hundred twenty-one billion, one thousand, twenty".