102249821 has 2 divisors, whose sum is σ = 102249822. Its totient is φ = 102249820.

The previous prime is 102249809. The next prime is 102249923. The reversal of 102249821 is 128942201.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 87703225 + 14546596 = 9365^2 + 3814^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-102249821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (102249221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 51124910 + 51124911.

It is an arithmetic number, because the mean of its divisors is an integer number (51124911).

Almost surely, 2^102249821 is an apocalyptic number.

It is an amenable number.

102249821 is a deficient number, since it is larger than the sum of its proper divisors (1).

102249821 is an equidigital number, since it uses as much as digits as its factorization.

102249821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 102249821 is about 10111.8653570941. The cubic root of 102249821 is about 467.6140147245.

The spelling of 102249821 in words is "one hundred two million, two hundred forty-nine thousand, eight hundred twenty-one".