221210019978 has 16 divisors (see below), whose sum is σ = 442426581696. Its totient is φ = 73735583040.

The previous prime is 221210019949. The next prime is 221210020049. The reversal of 221210019978 is 879910012122.

It is a super-4 number, since 4×221210019978⁴ (a number of 46 digits) contains 4444 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 241650 + ... + 707682.

It is an arithmetic number, because the mean of its divisors is an integer number (27651661356).

Almost surely, 2^221210019978 is an apocalyptic number.

221210019978 is an abundant number, since it is smaller than the sum of its proper divisors (221216561718).

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

221210019978 is a wasteful number, since it uses less digits than its factorization.

221210019978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 545149.

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

The spelling of 221210019978 in words is "two hundred twenty-one billion, two hundred ten million, nineteen thousand, nine hundred seventy-eight".