221409191779776 has 3360 divisors, whose sum is σ = 942578715133440. Its totient is φ = 49568827392000.

The previous prime is 221409191779757. The next prime is 221409191779777. The reversal of 221409191779776 is 677977191904122.

221409191779776 is a `hidden beast` number, since 2 + 21 + 409 + 191 + 7 + 7 + 9 + 7 + 7 + 6 = 666.

It is a super-2 number, since 2×221409191779776² (a number of 29 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221409191779777) by changing a digit.

It is a polite number, since it can be written in 479 ways as a sum of consecutive naturals, for example, 144617368131 + ... + 144617369661.

It is an arithmetic number, because the mean of its divisors is an integer number (280529379504).

Almost surely, 2^{221409191779776} is an apocalyptic number.

221409191779776 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221409191779776, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (471289357566720).

221409191779776 is an abundant number, since it is smaller than the sum of its proper divisors (721169523353664).

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

221409191779776 is a wasteful number, since it uses less digits than its factorization.

221409191779776 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1677 (or 1627 counting only the distinct ones).

The product of its (nonzero) digits is 168031584, while the sum is 72.

The spelling of 221409191779776 in words is "two hundred twenty-one trillion, four hundred nine billion, one hundred ninety-one million, seven hundred seventy-nine thousand, seven hundred seventy-six".