1661724460 has 72 divisors (see below), whose sum is σ = 3875790240. Its totient is φ = 597949440.

The previous prime is 1661724451. The next prime is 1661724487. The reversal of 1661724460 is 644271661.

It is a super-2 number, since 2×1661724460² = 5522656361924583200, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 231201 + ... + 238279.

It is an arithmetic number, because the mean of its divisors is an integer number (53830420).

Almost surely, 2^1661724460 is an apocalyptic number.

1661724460 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 1661724460, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1937895120).

1661724460 is an abundant number, since it is smaller than the sum of its proper divisors (2214065780).

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

1661724460 is a wasteful number, since it uses less digits than its factorization.

1661724460 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7207 (or 7194 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 37.

The square root of 1661724460 is about 40764.2546847112. The cubic root of 1661724460 is about 1184.4580144169.

The spelling of 1661724460 in words is "one billion, six hundred sixty-one million, seven hundred twenty-four thousand, four hundred sixty".