16665720 has 64 divisors (see below), whose sum is σ = 51732000. Its totient is φ = 4290048.

The previous prime is 16665713. The next prime is 16665739. The reversal of 16665720 is 2756661.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1086 + ... + 5874.

Almost surely, 2^16665720 is an apocalyptic number.

16665720 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 16665720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25866000).

16665720 is an abundant number, since it is smaller than the sum of its proper divisors (35066280).

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

16665720 is a wasteful number, since it uses less digits than its factorization.

16665720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4832 (or 4828 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 33.

The square root of 16665720 is about 4082.3669604777. The cubic root of 16665720 is about 255.4316411090.

The spelling of 16665720 in words is "sixteen million, six hundred sixty-five thousand, seven hundred twenty".