1156056021821 has 2 divisors, whose sum is σ = 1156056021822. Its totient is φ = 1156056021820.

The previous prime is 1156056021727. The next prime is 1156056021859. The reversal of 1156056021821 is 1281206506511.

It is an a-pointer prime, because the next prime (1156056021859) can be obtained adding 1156056021821 to its sum of digits (38).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 860896344025 + 295159677796 = 927845^2 + 543286^2 .

It is a cyclic number.

It is not a de Polignac number, because 1156056021821 - 2³⁸ = 881178114877 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1156056021881) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 578028010910 + 578028010911.

It is an arithmetic number, because the mean of its divisors is an integer number (578028010911).

Almost surely, 2^{1156056021821} is an apocalyptic number.

It is an amenable number.

1156056021821 is a deficient number, since it is larger than the sum of its proper divisors (1).

1156056021821 is an equidigital number, since it uses as much as digits as its factorization.

1156056021821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 28800, while the sum is 38.

The spelling of 1156056021821 in words is "one trillion, one hundred fifty-six billion, fifty-six million, twenty-one thousand, eight hundred twenty-one".