21613123212 has 12 divisors (see below), whose sum is σ = 50430620856. Its totient is φ = 7204374400.

The previous prime is 21613123211. The next prime is 21613123223. The reversal of 21613123212 is 21232131612.

It is a tau number, because it is divible by the number of its divisors (12).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (21613123211) 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, 900546789 + ... + 900546812.

It is an arithmetic number, because the mean of its divisors is an integer number (4202551738).

Almost surely, 2^21613123212 is an apocalyptic number.

It is an amenable number.

21613123212 is an abundant number, since it is smaller than the sum of its proper divisors (28817497644).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21613123212 is a wasteful number, since it uses less digits than its factorization.

21613123212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1801093608 (or 1801093606 counting only the distinct ones).

The product of its digits is 864, while the sum is 24.

Adding to 21613123212 its reverse (21232131612), we get a palindrome (42845254824).

The spelling of 21613123212 in words is "twenty-one billion, six hundred thirteen million, one hundred twenty-three thousand, two hundred twelve".