105656821 has 2 divisors, whose sum is σ = 105656822. Its totient is φ = 105656820.

The previous prime is 105656741. The next prime is 105656827. The reversal of 105656821 is 128656501.

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., 95765796 + 9891025 = 9786^2 + 3145^2 .

It is a cyclic number.

It is not a de Polignac number, because 105656821 - 2¹³ = 105648629 is a prime.

It is a super-4 number, since 4×105656821⁴ (a number of 33 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (105656827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 52828410 + 52828411.

It is an arithmetic number, because the mean of its divisors is an integer number (52828411).

Almost surely, 2^105656821 is an apocalyptic number.

It is an amenable number.

105656821 is a deficient number, since it is larger than the sum of its proper divisors (1).

105656821 is an equidigital number, since it uses as much as digits as its factorization.

105656821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 14400, while the sum is 34.

The square root of 105656821 is about 10278.9503841589. The cubic root of 105656821 is about 472.7510620436.

The spelling of 105656821 in words is "one hundred five million, six hundred fifty-six thousand, eight hundred twenty-one".