102021221 has 4 divisors (see below), whose sum is σ = 102048012. Its totient is φ = 101994432.

The previous prime is 102021197. The next prime is 102021251. The reversal of 102021221 is 122120201.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 53217025 + 48804196 = 7295^2 + 6986^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-102021221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (102021251) 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, 6500 + ... + 15693.

It is an arithmetic number, because the mean of its divisors is an integer number (25512003).

Almost surely, 2^102021221 is an apocalyptic number.

It is an amenable number.

102021221 is a deficient number, since it is larger than the sum of its proper divisors (26791).

102021221 is an equidigital number, since it uses as much as digits as its factorization.

102021221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26790.

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 102021221 is about 10100.5554797744. Note that the first 3 decimals coincide. The cubic root of 102021221 is about 467.2652730357.

Adding to 102021221 its reverse (122120201), we get a palindrome (224141422).

The spelling of 102021221 in words is "one hundred two million, twenty-one thousand, two hundred twenty-one".