12402221538 has 192 divisors, whose sum is σ = 31403151360. Its totient is φ = 3245018112.

The previous prime is 12402221477. The next prime is 12402221539. The reversal of 12402221538 is 83512220421.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (12402221539) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 25466331 + ... + 25466817.

It is an arithmetic number, because the mean of its divisors is an integer number (163558080).

Almost surely, 2^12402221538 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 12402221538, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15701575680).

12402221538 is an abundant number, since it is smaller than the sum of its proper divisors (19000929822).

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

12402221538 is a wasteful number, since it uses less digits than its factorization.

12402221538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 669 (or 662 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 30.

Adding to 12402221538 its reverse (83512220421), we get a palindrome (95914441959).

The spelling of 12402221538 in words is "twelve billion, four hundred two million, two hundred twenty-one thousand, five hundred thirty-eight".