221543165025551 has 4 divisors (see below), whose sum is σ = 223503724008192. Its totient is φ = 219582606042912.

The previous prime is 221543165025487. The next prime is 221543165025571. The reversal of 221543165025551 is 155520561345122.

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

It is a cyclic number.

It is not a de Polignac number, because 221543165025551 - 2⁶ = 221543165025487 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221543165025496 and 221543165025505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221543165025571) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 980279491151 + ... + 980279491376.

It is an arithmetic number, because the mean of its divisors is an integer number (55875931002048).

Almost surely, 2^{221543165025551} is an apocalyptic number.

221543165025551 is a deficient number, since it is larger than the sum of its proper divisors (1960558982641).

221543165025551 is a wasteful number, since it uses less digits than its factorization.

221543165025551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1960558982640.

The product of its (nonzero) digits is 1800000, while the sum is 47.

The spelling of 221543165025551 in words is "two hundred twenty-one trillion, five hundred forty-three billion, one hundred sixty-five million, twenty-five thousand, five hundred fifty-one".