221240011555 has 4 divisors (see below), whose sum is σ = 265488013872. Its totient is φ = 176992009240.

The previous prime is 221240011543. The next prime is 221240011567. The reversal of 221240011555 is 555110042122.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 555110042122 = 2 ⋅277555021061.

It is an interprime number because it is at equal distance from previous prime (221240011543) and next prime (221240011567).

It is not a de Polignac number, because 221240011555 - 2⁵ = 221240011523 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22124001151 + ... + 22124001160.

It is an arithmetic number, because the mean of its divisors is an integer number (66372003468).

Almost surely, 2^221240011555 is an apocalyptic number.

221240011555 is a deficient number, since it is larger than the sum of its proper divisors (44248002317).

221240011555 is an equidigital number, since it uses as much as digits as its factorization.

221240011555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44248002316.

The product of its (nonzero) digits is 4000, while the sum is 28.

Adding to 221240011555 its reverse (555110042122), we get a palindrome (776350053677).

The spelling of 221240011555 in words is "two hundred twenty-one billion, two hundred forty million, eleven thousand, five hundred fifty-five".