1000001220021 has 32 divisors (see below), whose sum is σ = 1559650380800. Its totient is φ = 631501032240.

The previous prime is 1000001220011. The next prime is 1000001220073. The reversal of 1000001220021 is 1200221000001.

It is not a de Polignac number, because 1000001220021 - 2⁹ = 1000001219509 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1000001219985 and 1000001220012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1000001220011) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4146270 + ... + 4380816.

It is an arithmetic number, because the mean of its divisors is an integer number (48739074400).

Almost surely, 2^{1000001220021} is an apocalyptic number.

It is an amenable number.

1000001220021 is a deficient number, since it is larger than the sum of its proper divisors (559649160779).

1000001220021 is a wasteful number, since it uses less digits than its factorization.

1000001220021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 242886 (or 242880 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 1000001220021 its reverse (1200221000001), we get a palindrome (2200222220022).

The spelling of 1000001220021 in words is "one trillion, one million, two hundred twenty thousand, twenty-one".