1721697120 has 480 divisors, whose sum is σ = 7146105120. Its totient is φ = 384860160.

The previous prime is 1721697119. The next prime is 1721697149. The reversal of 1721697120 is 217961271.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (480).

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 79 ways as a sum of consecutive naturals, for example, 1852816 + ... + 1853744.

It is an arithmetic number, because the mean of its divisors is an integer number (14887719).

Almost surely, 2^1721697120 is an apocalyptic number.

1721697120 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 1721697120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3573052560).

1721697120 is an abundant number, since it is smaller than the sum of its proper divisors (5424408000).

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

1721697120 is a wasteful number, since it uses less digits than its factorization.

1721697120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 980 (or 963 counting only the distinct ones).

The product of its (nonzero) digits is 10584, while the sum is 36.

The square root of 1721697120 is about 41493.3382604967. The cubic root of 1721697120 is about 1198.5392224958.

The spelling of 1721697120 in words is "one billion, seven hundred twenty-one million, six hundred ninety-seven thousand, one hundred twenty".