21231231219 has 16 divisors (see below), whose sum is σ = 34313101440. Its totient is φ = 12867412680.

The previous prime is 21231231211. The next prime is 21231231221. The reversal of 21231231219 is 91213213212.

21231231219 is a `hidden beast` number, since 21 + 2 + 312 + 312 + 19 = 666.

It is not a de Polignac number, because 21231231219 - 2³ = 21231231211 is a prime.

It is a super-2 number, since 2×21231231219² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 21231231192 and 21231231201.

It is not an unprimeable number, because it can be changed into a prime (21231231211) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 35742517 + ... + 35743110.

It is an arithmetic number, because the mean of its divisors is an integer number (2144568840).

Almost surely, 2^21231231219 is an apocalyptic number.

21231231219 is a deficient number, since it is larger than the sum of its proper divisors (13081870221).

21231231219 is a wasteful number, since it uses less digits than its factorization.

21231231219 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71485647 (or 71485641 counting only the distinct ones).

The product of its digits is 1296, while the sum is 27.

The spelling of 21231231219 in words is "twenty-one billion, two hundred thirty-one million, two hundred thirty-one thousand, two hundred nineteen".