111111255421 has 4 divisors (see below), whose sum is σ = 111113223100. Its totient is φ = 111109287744.

The previous prime is 111111255419. The next prime is 111111255433. The reversal of 111111255421 is 124552111111.

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 15002575225 + 96108680196 = 122485^2 + 310014^2 .

It is a cyclic number.

It is not a de Polignac number, because 111111255421 - 2¹ = 111111255419 is a prime.

It is a super-2 number, since 2×111111255421² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (111111255401) 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, 896556 + ... + 1012933.

It is an arithmetic number, because the mean of its divisors is an integer number (27778305775).

Almost surely, 2^111111255421 is an apocalyptic number.

It is an amenable number.

111111255421 is a deficient number, since it is larger than the sum of its proper divisors (1967679).

111111255421 is an equidigital number, since it uses as much as digits as its factorization.

111111255421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1967678.

The product of its digits is 400, while the sum is 25.

Adding to 111111255421 its reverse (124552111111), we get a palindrome (235663366532).

The spelling of 111111255421 in words is "one hundred eleven billion, one hundred eleven million, two hundred fifty-five thousand, four hundred twenty-one".