821142256553 has 2 divisors, whose sum is σ = 821142256554. Its totient is φ = 821142256552.

The previous prime is 821142256549. The next prime is 821142256591. The reversal of 821142256553 is 355652241128.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 760230535744 + 60911720809 = 871912^2 + 246803^2 .

It is a cyclic number.

It is not a de Polignac number, because 821142256553 - 2² = 821142256549 is a prime.

It is not a weakly prime, because it can be changed into another prime (821142256153) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410571128276 + 410571128277.

It is an arithmetic number, because the mean of its divisors is an integer number (410571128277).

Almost surely, 2^821142256553 is an apocalyptic number.

It is an amenable number.

821142256553 is a deficient number, since it is larger than the sum of its proper divisors (1).

821142256553 is an equidigital number, since it uses as much as digits as its factorization.

821142256553 is an evil number, because the sum of its binary digits is even.

The product of its digits is 576000, while the sum is 44.

The spelling of 821142256553 in words is "eight hundred twenty-one billion, one hundred forty-two million, two hundred fifty-six thousand, five hundred fifty-three".