221020001000 has 32 divisors (see below), whose sum is σ = 517186804680. Its totient is φ = 88408000000.

The previous prime is 221020000997. The next prime is 221020001009. The reversal of 221020001000 is 100020122.

It can be written as a sum of positive squares in 4 ways, for example, as 11232184324 + 209787816676 = 105982^2 + 458026^2 .

It is a Harshad number since it is a multiple of its sum of digits (8).

It is not an unprimeable number, because it can be changed into a prime (221020001009) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 110509001 + ... + 110511000.

Almost surely, 2^221020001000 is an apocalyptic number.

221020001000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221020001000 is an abundant number, since it is smaller than the sum of its proper divisors (296166803680).

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

221020001000 is a wasteful number, since it uses less digits than its factorization.

221020001000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 221020022 (or 221020008 counting only the distinct ones).

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

Adding to 221020001000 its reverse (100020122), we get a palindrome (221120021122).

The spelling of 221020001000 in words is "two hundred twenty-one billion, twenty million, one thousand".