1021645563121 has 4 divisors (see below), whose sum is σ = 1056874720500. Its totient is φ = 986416405744.

The previous prime is 1021645563091. The next prime is 1021645563137. The reversal of 1021645563121 is 1213655461201.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 271507692096 + 750137871025 = 521064^2 + 866105^2 .

It is a cyclic number.

It is not a de Polignac number, because 1021645563121 - 2⁵ = 1021645563089 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1021645567121) 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 in 3 ways as a sum of consecutive naturals, for example, 17614578646 + ... + 17614578703.

It is an arithmetic number, because the mean of its divisors is an integer number (264218680125).

Almost surely, 2^{1021645563121} is an apocalyptic number.

It is an amenable number.

1021645563121 is a deficient number, since it is larger than the sum of its proper divisors (35229157379).

1021645563121 is an equidigital number, since it uses as much as digits as its factorization.

1021645563121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35229157378.

The product of its (nonzero) digits is 43200, while the sum is 37.

The spelling of 1021645563121 in words is "one trillion, twenty-one billion, six hundred forty-five million, five hundred sixty-three thousand, one hundred twenty-one".