21312212013 has 6 divisors (see below), whose sum is σ = 30784306254. Its totient is φ = 14208141336.

The previous prime is 21312211951. The next prime is 21312212093. The reversal of 21312212013 is 31021221312.

It can be written as a sum of positive squares in only one way, i.e., 20568722724 + 743489289 = 143418^2 + 27267^2 .

It is not a de Polignac number, because 21312212013 - 2¹⁰ = 21312210989 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21312212093) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1184011770 + ... + 1184011787.

It is an arithmetic number, because the mean of its divisors is an integer number (5130717709).

Almost surely, 2^21312212013 is an apocalyptic number.

It is an amenable number.

21312212013 is a deficient number, since it is larger than the sum of its proper divisors (9472094241).

21312212013 is a wasteful number, since it uses less digits than its factorization.

21312212013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2368023563 (or 2368023560 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 21312212013 its reverse (31021221312), we get a palindrome (52333433325).

It can be divided in two parts, 2131 and 2212013, that added together give a square (2214144 = 1488²).

The spelling of 21312212013 in words is "twenty-one billion, three hundred twelve million, two hundred twelve thousand, thirteen".