1022100021 has 6 divisors (see below), whose sum is σ = 1476366710. Its totient is φ = 681400008.

The previous prime is 1022100007. The next prime is 1022100031. The reversal of 1022100021 is 1200012201.

It can be written as a sum of positive squares in only one way, i.e., 866124900 + 155975121 = 29430^2 + 12489^2 .

It is not a de Polignac number, because 1022100021 - 2¹⁵ = 1022067253 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9), and also a Moran number because the ratio is a prime number: 113566669 = 1022100021 / (1 + 0 + 2 + 2 + 1 + 0 + 0 + 0 + 2 + 1).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1022099976 and 1022100012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1022100031) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 56783326 + ... + 56783343.

Almost surely, 2^1022100021 is an apocalyptic number.

It is an amenable number.

1022100021 is a deficient number, since it is larger than the sum of its proper divisors (454266689).

1022100021 is a wasteful number, since it uses less digits than its factorization.

1022100021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 113566675 (or 113566672 counting only the distinct ones).

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

The square root of 1022100021 is about 31970.2990445820. The cubic root of 1022100021 is about 1007.3130624151.

Adding to 1022100021 its reverse (1200012201), we get a palindrome (2222112222).

The spelling of 1022100021 in words is "one billion, twenty-two million, one hundred thousand, twenty-one".