1720721226 has 32 divisors (see below), whose sum is σ = 3934327680. Its totient is φ = 491478336.

The previous prime is 1720721201. The next prime is 1720721227. The reversal of 1720721226 is 6221270271.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1720721193 and 1720721202.

It is not an unprimeable number, because it can be changed into a prime (1720721227) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 219120 + ... + 226836.

It is an arithmetic number, because the mean of its divisors is an integer number (122947740).

Almost surely, 2^1720721226 is an apocalyptic number.

1720721226 is an abundant number, since it is smaller than the sum of its proper divisors (2213606454).

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

1720721226 is a wasteful number, since it uses less digits than its factorization.

1720721226 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13038.

The product of its (nonzero) digits is 4704, while the sum is 30.

The square root of 1720721226 is about 41481.5769468809. The cubic root of 1720721226 is about 1198.3127273154.

Adding to 1720721226 its reverse (6221270271), we get a palindrome (7941991497).

The spelling of 1720721226 in words is "one billion, seven hundred twenty million, seven hundred twenty-one thousand, two hundred twenty-six".