12211209978 has 32 divisors (see below), whose sum is σ = 28044887040. Its totient is φ = 3505610160.

The previous prime is 12211209971. The next prime is 12211209991. The reversal of 12211209978 is 87990211221.

It is a super-2 number, since 2×12211209978² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (12211209971) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4867650 + ... + 4870157.

It is an arithmetic number, because the mean of its divisors is an integer number (876402720).

Almost surely, 2^12211209978 is an apocalyptic number.

12211209978 is an abundant number, since it is smaller than the sum of its proper divisors (15833677062).

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

12211209978 is a wasteful number, since it uses less digits than its factorization.

12211209978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9737842.

The product of its (nonzero) digits is 36288, while the sum is 42.

The spelling of 12211209978 in words is "twelve billion, two hundred eleven million, two hundred nine thousand, nine hundred seventy-eight".