1720257220 has 24 divisors (see below), whose sum is σ = 3940953408. Its totient is φ = 625548000.

The previous prime is 1720257179. The next prime is 1720257229. The reversal of 1720257220 is 227520271.

It is not an unprimeable number, because it can be changed into a prime (1720257229) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3909456 + ... + 3909895.

It is an arithmetic number, because the mean of its divisors is an integer number (164206392).

Almost surely, 2^1720257220 is an apocalyptic number.

1720257220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1720257220 is an abundant number, since it is smaller than the sum of its proper divisors (2220696188).

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

1720257220 is a wasteful number, since it uses less digits than its factorization.

1720257220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7819371 (or 7819369 counting only the distinct ones).

The product of its (nonzero) digits is 3920, while the sum is 28.

The square root of 1720257220 is about 41475.9836531938. The cubic root of 1720257220 is about 1198.2050061512.

Adding to 1720257220 its reverse (227520271), we get a palindrome (1947777491).

The spelling of 1720257220 in words is "one billion, seven hundred twenty million, two hundred fifty-seven thousand, two hundred twenty".