21215478181043 has 4 divisors (see below), whose sum is σ = 21222101811528. Its totient is φ = 21208854550560.

The previous prime is 21215478180961. The next prime is 21215478181049. The reversal of 21215478181043 is 34018187451212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21215478181043 - 2²² = 21215473986739 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21215478181049) 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, 3311810438 + ... + 3311816843.

It is an arithmetic number, because the mean of its divisors is an integer number (5305525452882).

Almost surely, 2^{21215478181043} is an apocalyptic number.

21215478181043 is a deficient number, since it is larger than the sum of its proper divisors (6623630485).

21215478181043 is an equidigital number, since it uses as much as digits as its factorization.

21215478181043 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6623630484.

The product of its (nonzero) digits is 430080, while the sum is 47.

The spelling of 21215478181043 in words is "twenty-one trillion, two hundred fifteen billion, four hundred seventy-eight million, one hundred eighty-one thousand, forty-three".