13221335981 has 4 divisors (see below), whose sum is σ = 15110098272. Its totient is φ = 11332573692.

The previous prime is 13221335977. The next prime is 13221335983. The reversal of 13221335981 is 18953312231.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 13221335981 - 2² = 13221335977 is a prime.

It is a super-2 number, since 2×13221335981² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13221335983) 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, 944381135 + ... + 944381148.

It is an arithmetic number, because the mean of its divisors is an integer number (3777524568).

Almost surely, 2^13221335981 is an apocalyptic number.

It is an amenable number.

13221335981 is a deficient number, since it is larger than the sum of its proper divisors (1888762291).

13221335981 is an equidigital number, since it uses as much as digits as its factorization.

13221335981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1888762290.

The product of its digits is 38880, while the sum is 38.

The spelling of 13221335981 in words is "thirteen billion, two hundred twenty-one million, three hundred thirty-five thousand, nine hundred eighty-one".