221707720 has 48 divisors (see below), whose sum is σ = 540183060. Its totient is φ = 81858816.

The previous prime is 221707667. The next prime is 221707721. The reversal of 221707720 is 27707122.

It can be written as a sum of positive squares in 6 ways, for example, as 88397604 + 133310116 = 9402^2 + 11546^2 .

It is not an unprimeable number, because it can be changed into a prime (221707721) 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 11 ways as a sum of consecutive naturals, for example, 9639 + ... + 23158.

Almost surely, 2^221707720 is an apocalyptic number.

221707720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221707720 is an abundant number, since it is smaller than the sum of its proper divisors (318475340).

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

221707720 is a wasteful number, since it uses less digits than its factorization.

221707720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32834 (or 32817 counting only the distinct ones).

The product of its (nonzero) digits is 2744, while the sum is 28.

The square root of 221707720 is about 14889.8529206974. The cubic root of 221707720 is about 605.2390467602.

It can be divided in two parts, 22170 and 7720, that added together give a triangular number (29890 = T₂₄₄).

The spelling of 221707720 in words is "two hundred twenty-one million, seven hundred seven thousand, seven hundred twenty".