1721880 has 48 divisors (see below), whose sum is σ = 5597280. Its totient is φ = 459072.

The previous prime is 1721857. The next prime is 1721887. The reversal of 1721880 is 881271.

1721880 = 39² + 40² + ... + 173².

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1721887) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2032 + ... + 2751.

It is an arithmetic number, because the mean of its divisors is an integer number (116610).

2^1721880 is an apocalyptic number.

1721880 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1721880 is an abundant number, since it is smaller than the sum of its proper divisors (3875400).

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

1721880 is a wasteful number, since it uses less digits than its factorization.

1721880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4800 (or 4793 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 27.

The square root of 1721880 is about 1312.2042523937. The cubic root of 1721880 is about 119.8581657581.

It can be divided in two parts, 1721 and 880, that added together give a square (2601 = 51²).

The spelling of 1721880 in words is "one million, seven hundred twenty-one thousand, eight hundred eighty".