1721720448 has 240 divisors, whose sum is σ = 5962111650. Its totient is φ = 491774976.

The previous prime is 1721720443. The next prime is 1721720461. The reversal of 1721720448 is 8440271271.

It can be written as a sum of positive squares in only one way, i.e., 1008189504 + 713530944 = 31752^2 + 26712^2 .

It is a super-2 number, since 2×1721720448² = 5928642602122641408, which contains 22 as substring.

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

It is not an unprimeable number, because it can be changed into a prime (1721720443) by changing a digit.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 506338 + ... + 509726.

Almost surely, 2^1721720448 is an apocalyptic number.

1721720448 is a gapful number since it is divisible by the number (18) 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 1721720448, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2981055825).

1721720448 is an abundant number, since it is smaller than the sum of its proper divisors (4240391202).

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

1721720448 is an equidigital number, since it uses as much as digits as its factorization.

1721720448 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3429 (or 3401 counting only the distinct ones).

The product of its (nonzero) digits is 25088, while the sum is 36.

The square root of 1721720448 is about 41493.6193649096. The cubic root of 1721720448 is about 1198.5446356424.

The spelling of 1721720448 in words is "one billion, seven hundred twenty-one million, seven hundred twenty thousand, four hundred forty-eight".