221221999955 has 16 divisors (see below), whose sum is σ = 289765037664. Its totient is φ = 160796878080.

The previous prime is 221221999949. The next prime is 221221999969. The reversal of 221221999955 is 559999122122.

It is a happy number.

It is not a de Polignac number, because 221221999955 - 2⁶ = 221221999891 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 221221999955.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1050824 + ... + 1243653.

It is an arithmetic number, because the mean of its divisors is an integer number (18110314854).

Almost surely, 2^221221999955 is an apocalyptic number.

221221999955 is a deficient number, since it is larger than the sum of its proper divisors (68543037709).

221221999955 is a wasteful number, since it uses less digits than its factorization.

221221999955 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2296246.

The product of its digits is 2624400, while the sum is 56.

The spelling of 221221999955 in words is "two hundred twenty-one billion, two hundred twenty-one million, nine hundred ninety-nine thousand, nine hundred fifty-five".