2155310251421 has 4 divisors (see below), whose sum is σ = 2155639162332. Its totient is φ = 2154981340512.

The previous prime is 2155310251363. The next prime is 2155310251447. The reversal of 2155310251421 is 1241520135512.

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 817785619225 + 1337524632196 = 904315^2 + 1156514^2 .

It is a cyclic number.

It is not a de Polignac number, because 2155310251421 - 2⁶ = 2155310251357 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2155310251921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 164445626 + ... + 164458731.

It is an arithmetic number, because the mean of its divisors is an integer number (538909790583).

Almost surely, 2^{2155310251421} is an apocalyptic number.

It is an amenable number.

2155310251421 is a deficient number, since it is larger than the sum of its proper divisors (328910911).

2155310251421 is an equidigital number, since it uses as much as digits as its factorization.

2155310251421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 328910910.

The product of its (nonzero) digits is 12000, while the sum is 32.

Adding to 2155310251421 its reverse (1241520135512), we get a palindrome (3396830386933).

The spelling of 2155310251421 in words is "two trillion, one hundred fifty-five billion, three hundred ten million, two hundred fifty-one thousand, four hundred twenty-one".