105087821 has 2 divisors, whose sum is σ = 105087822. Its totient is φ = 105087820.

The previous prime is 105087781. The next prime is 105087823. The reversal of 105087821 is 128780501.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 101808100 + 3279721 = 10090^2 + 1811^2 .

It is a cyclic number.

It is not a de Polignac number, because 105087821 - 2⁶ = 105087757 is a prime.

It is a super-2 number, since 2×105087821² = 22086900245056082, which contains 22 as substring.

Together with 105087823, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (105087823) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 52543910 + 52543911.

It is an arithmetic number, because the mean of its divisors is an integer number (52543911).

Almost surely, 2^105087821 is an apocalyptic number.

It is an amenable number.

105087821 is a deficient number, since it is larger than the sum of its proper divisors (1).

105087821 is an equidigital number, since it uses as much as digits as its factorization.

105087821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4480, while the sum is 32.

The square root of 105087821 is about 10251.2350963189. The cubic root of 105087821 is about 471.9008891896.

The spelling of 105087821 in words is "one hundred five million, eighty-seven thousand, eight hundred twenty-one".