1721920400 has 60 divisors (see below), whose sum is σ = 4195249344. Its totient is φ = 679056000.

The previous prime is 1721920373. The next prime is 1721920411. The reversal of 1721920400 is 40291271.

It is a self number, because there is not a number n which added to its sum of digits gives 1721920400.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1916 + ... + 58715.

Almost surely, 2^1721920400 is an apocalyptic number.

1721920400 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 1721920400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2097624672).

1721920400 is an abundant number, since it is smaller than the sum of its proper divisors (2473328944).

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

1721920400 is a wasteful number, since it uses less digits than its factorization.

1721920400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60720 (or 60709 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 26.

The square root of 1721920400 is about 41496.0287256504. The cubic root of 1721920400 is about 1198.5910315058.

The spelling of 1721920400 in words is "one billion, seven hundred twenty-one million, nine hundred twenty thousand, four hundred".