221534403653021 has 4 divisors (see below), whose sum is σ = 221706268979100. Its totient is φ = 221362538326944.

The previous prime is 221534403652997. The next prime is 221534403653023. The reversal of 221534403653021 is 120356304435122.

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 195009215284900 + 26525188368121 = 13964570^2 + 5150261^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221534403653021 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 221534403653021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221534403653023) 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, 85932661106 + ... + 85932663683.

It is an arithmetic number, because the mean of its divisors is an integer number (55426567244775).

Almost surely, 2^{221534403653021} is an apocalyptic number.

It is an amenable number.

221534403653021 is a deficient number, since it is larger than the sum of its proper divisors (171865326079).

221534403653021 is a wasteful number, since it uses less digits than its factorization.

221534403653021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171865326078.

The product of its (nonzero) digits is 518400, while the sum is 41.

The spelling of 221534403653021 in words is "two hundred twenty-one trillion, five hundred thirty-four billion, four hundred three million, six hundred fifty-three thousand, twenty-one".