221534404156261 has 4 divisors (see below), whose sum is σ = 253182176178592. Its totient is φ = 189886632133932.

The previous prime is 221534404156259. The next prime is 221534404156297. The reversal of 221534404156261 is 162651404435122.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 221534404156261 - 2¹ = 221534404156259 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221534404156361) 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, 15823886011155 + ... + 15823886011168.

It is an arithmetic number, because the mean of its divisors is an integer number (63295544044648).

Almost surely, 2^{221534404156261} is an apocalyptic number.

It is an amenable number.

221534404156261 is a deficient number, since it is larger than the sum of its proper divisors (31647772022331).

221534404156261 is an equidigital number, since it uses as much as digits as its factorization.

221534404156261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31647772022330.

The product of its (nonzero) digits is 1382400, while the sum is 46.

The spelling of 221534404156261 in words is "two hundred twenty-one trillion, five hundred thirty-four billion, four hundred four million, one hundred fifty-six thousand, two hundred sixty-one".