102021221209 has 4 divisors (see below), whose sum is σ = 102022814116. Its totient is φ = 102019628304.

The previous prime is 102021221171. The next prime is 102021221213. The reversal of 102021221209 is 902122120201.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 902122120201 = 110581 ⋅8158021.

It can be written as a sum of positive squares in 2 ways, for example, as 52774953984 + 49246267225 = 229728^2 + 221915^2 .

It is a cyclic number.

It is not a de Polignac number, because 102021221209 - 2¹¹ = 102021219161 is a prime.

It is a super-2 number, since 2×102021221209² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 102021221209.

It is not an unprimeable number, because it can be changed into a prime (102021224209) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 696174 + ... + 829879.

It is an arithmetic number, because the mean of its divisors is an integer number (25505703529).

Almost surely, 2^102021221209 is an apocalyptic number.

It is an amenable number.

102021221209 is a deficient number, since it is larger than the sum of its proper divisors (1592907).

102021221209 is an equidigital number, since it uses as much as digits as its factorization.

102021221209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1592906.

The product of its (nonzero) digits is 288, while the sum is 22.

The spelling of 102021221209 in words is "one hundred two billion, twenty-one million, two hundred twenty-one thousand, two hundred nine".