1721378520 has 512 divisors, whose sum is σ = 6508512000. Its totient is φ = 402554880.

The previous prime is 1721378497. The next prime is 1721378521. The reversal of 1721378520 is 258731271.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1721378521) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 28219290 + ... + 28219350.

Almost surely, 2^1721378520 is an apocalyptic number.

1721378520 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 1721378520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3254256000).

1721378520 is an abundant number, since it is smaller than the sum of its proper divisors (4787133480).

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

1721378520 is a wasteful number, since it uses less digits than its factorization.

1721378520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 180 (or 170 counting only the distinct ones).

The product of its (nonzero) digits is 23520, while the sum is 36.

The square root of 1721378520 is about 41489.4989123754. The cubic root of 1721378520 is about 1198.4652880528.

The spelling of 1721378520 in words is "one billion, seven hundred twenty-one million, three hundred seventy-eight thousand, five hundred twenty".