1660421620 has 288 divisors, whose sum is σ = 4542241536. Its totient is φ = 503193600.

The previous prime is 1660421563. The next prime is 1660421621. The reversal of 1660421620 is 261240661.

It is a super-3 number, since 3×1660421620³ (a number of 29 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1660421621) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 23386185 + ... + 23386255.

It is an arithmetic number, because the mean of its divisors is an integer number (15771672).

Almost surely, 2^1660421620 is an apocalyptic number.

1660421620 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 1660421620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2271120768).

1660421620 is an abundant number, since it is smaller than the sum of its proper divisors (2881819916).

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

1660421620 is a wasteful number, since it uses less digits than its factorization.

1660421620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 171 (or 156 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 1660421620 is about 40748.2713743786. The cubic root of 1660421620 is about 1184.1483837117.

The spelling of 1660421620 in words is "one billion, six hundred sixty million, four hundred twenty-one thousand, six hundred twenty".