102102821 has 4 divisors (see below), whose sum is σ = 102369792. Its totient is φ = 101835852.

The previous prime is 102102817. The next prime is 102102829. The reversal of 102102821 is 128201201.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 102102821 - 2² = 102102817 is a prime.

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 102102821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (102102829) 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, 132911 + ... + 133676.

It is an arithmetic number, because the mean of its divisors is an integer number (25592448).

Almost surely, 2^102102821 is an apocalyptic number.

It is an amenable number.

102102821 is a deficient number, since it is larger than the sum of its proper divisors (266971).

102102821 is an equidigital number, since it uses as much as digits as its factorization.

102102821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 266970.

The product of its (nonzero) digits is 64, while the sum is 17.

The square root of 102102821 is about 10104.5940541914. The cubic root of 102102821 is about 467.3898179910.

It can be divided in two parts, 10210 and 2821, that added together give a palindrome (13031).

The spelling of 102102821 in words is "one hundred two million, one hundred two thousand, eight hundred twenty-one".