221256509760 has 672 divisors, whose sum is σ = 899710785792. Its totient is φ = 49200168960.

The previous prime is 221256509743. The next prime is 221256509767. The reversal of 221256509760 is 67905652122.

221256509760 is a `hidden beast` number, since 2 + 2 + 12 + 565 + 0 + 9 + 76 + 0 = 666.

It is a super-2 number, since 2×221256509760² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221256509767) 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 95 ways as a sum of consecutive naturals, for example, 68775672 + ... + 68778888.

It is an arithmetic number, because the mean of its divisors is an integer number (1338855336).

Almost surely, 2^221256509760 is an apocalyptic number.

221256509760 is a gapful number since it is divisible by the number (20) 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 221256509760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (449855392896).

221256509760 is an abundant number, since it is smaller than the sum of its proper divisors (678454276032).

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

221256509760 is a wasteful number, since it uses less digits than its factorization.

221256509760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3431 (or 3418 counting only the distinct ones).

The product of its (nonzero) digits is 453600, while the sum is 45.

The spelling of 221256509760 in words is "two hundred twenty-one billion, two hundred fifty-six million, five hundred nine thousand, seven hundred sixty".