21212013131 has 4 divisors (see below), whose sum is σ = 21247308264. Its totient is φ = 21176718000.

The previous prime is 21212013113. The next prime is 21212013149. The reversal of 21212013131 is 13131021212.

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

It is an interprime number because it is at equal distance from previous prime (21212013113) and next prime (21212013149).

It is a cyclic number.

It is not a de Polignac number, because 21212013131 - 2¹⁴ = 21211996747 is a prime.

It is a super-2 number, since 2×21212013131² (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 (21212013101) 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, 17646665 + ... + 17647866.

It is an arithmetic number, because the mean of its divisors is an integer number (5311827066).

Almost surely, 2^21212013131 is an apocalyptic number.

21212013131 is a deficient number, since it is larger than the sum of its proper divisors (35295133).

21212013131 is an equidigital number, since it uses as much as digits as its factorization.

21212013131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35295132.

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 21212013131 its reverse (13131021212), we get a palindrome (34343034343).

The spelling of 21212013131 in words is "twenty-one billion, two hundred twelve million, thirteen thousand, one hundred thirty-one".