221221019977 has 8 divisors (see below), whose sum is σ = 225535871880. Its totient is φ = 216911385600.

The previous prime is 221221019909. The next prime is 221221019993. The reversal of 221221019977 is 779910122122.

It can be written as a sum of positive squares in 4 ways, for example, as 134325182016 + 86895837961 = 366504^2 + 294781^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 221221019977 - 2²³ = 221212631369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221221019077) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1218702 + ... + 1388407.

It is an arithmetic number, because the mean of its divisors is an integer number (28191983985).

Almost surely, 2^221221019977 is an apocalyptic number.

It is an amenable number.

221221019977 is a deficient number, since it is larger than the sum of its proper divisors (4314851903).

221221019977 is a wasteful number, since it uses less digits than its factorization.

221221019977 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2608763.

The product of its (nonzero) digits is 63504, while the sum is 43.

The spelling of 221221019977 in words is "two hundred twenty-one billion, two hundred twenty-one million, nineteen thousand, nine hundred seventy-seven".