2145561554521 has 32 divisors (see below), whose sum is σ = 2681793792000. Its totient is φ = 1667613588480.

The previous prime is 2145561554459. The next prime is 2145561554639. The reversal of 2145561554521 is 1254551655412.

It is a de Polignac number, because none of the positive numbers 2^k-2145561554521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2145561554221) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 136313470 + ... + 136329208.

It is an arithmetic number, because the mean of its divisors is an integer number (83806056000).

Almost surely, 2^{2145561554521} is an apocalyptic number.

It is an amenable number.

2145561554521 is a deficient number, since it is larger than the sum of its proper divisors (536232237479).

2145561554521 is a wasteful number, since it uses less digits than its factorization.

2145561554521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20149.

The product of its digits is 1200000, while the sum is 46.

The spelling of 2145561554521 in words is "two trillion, one hundred forty-five billion, five hundred sixty-one million, five hundred fifty-four thousand, five hundred twenty-one".