212021199978 has 32 divisors (see below), whose sum is σ = 485804814720. Its totient is φ = 60429369600.

The previous prime is 212021199961. The next prime is 212021199979. The reversal of 212021199978 is 879991120212.

212021199978 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×212021199978² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 212021199978.

It is not an unprimeable number, because it can be changed into a prime (212021199979) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6154123 + ... + 6188478.

It is an arithmetic number, because the mean of its divisors is an integer number (15181400460).

Almost surely, 2^212021199978 is an apocalyptic number.

212021199978 is an abundant number, since it is smaller than the sum of its proper divisors (273783614742).

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

212021199978 is a wasteful number, since it uses less digits than its factorization.

212021199978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12343022.

The product of its (nonzero) digits is 326592, while the sum is 51.

The spelling of 212021199978 in words is "two hundred twelve billion, twenty-one million, one hundred ninety-nine thousand, nine hundred seventy-eight".