1720717920 has 216 divisors, whose sum is σ = 5979826944. Its totient is φ = 450551808.

The previous prime is 1720717909. The next prime is 1720717931. The reversal of 1720717920 is 297170271.

It is an interprime number because it is at equal distance from previous prime (1720717909) and next prime (1720717931).

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 13548897 + ... + 13549023.

It is an arithmetic number, because the mean of its divisors is an integer number (27684384).

Almost surely, 2^1720717920 is an apocalyptic number.

1720717920 is a gapful number since it is divisible by the number (10) 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 1720717920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2989913472).

1720717920 is an abundant number, since it is smaller than the sum of its proper divisors (4259109024).

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

1720717920 is a wasteful number, since it uses less digits than its factorization.

1720717920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 342 (or 234 counting only the distinct ones).

The product of its (nonzero) digits is 12348, while the sum is 36.

The square root of 1720717920 is about 41481.5370978463. The cubic root of 1720717920 is about 1198.3119598806.

The spelling of 1720717920 in words is "one billion, seven hundred twenty million, seven hundred seventeen thousand, nine hundred twenty".