21184429081 has 4 divisors (see below), whose sum is σ = 21291964452. Its totient is φ = 21076893712.

The previous prime is 21184429067. The next prime is 21184429087. The reversal of 21184429081 is 18092448112.

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 20884585225 + 299843856 = 144515^2 + 17316^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21184429081 is a prime.

It is a super-2 number, since 2×21184429081² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21184429087) 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, 53767390 + ... + 53767783.

It is an arithmetic number, because the mean of its divisors is an integer number (5322991113).

Almost surely, 2^21184429081 is an apocalyptic number.

It is an amenable number.

21184429081 is a deficient number, since it is larger than the sum of its proper divisors (107535371).

21184429081 is a wasteful number, since it uses less digits than its factorization.

21184429081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107535370.

The product of its (nonzero) digits is 36864, while the sum is 40.

The spelling of 21184429081 in words is "twenty-one billion, one hundred eighty-four million, four hundred twenty-nine thousand, eighty-one".