16661720 has 16 divisors (see below), whose sum is σ = 37488960. Its totient is φ = 6664672.

The previous prime is 16661713. The next prime is 16661741. The reversal of 16661720 is 2716661.

It is a super-2 number, since 2×16661720² = 555225826716800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 208232 + ... + 208311.

It is an arithmetic number, because the mean of its divisors is an integer number (2343060).

Almost surely, 2^16661720 is an apocalyptic number.

16661720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

16661720 is an abundant number, since it is smaller than the sum of its proper divisors (20827240).

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

16661720 is a wasteful number, since it uses less digits than its factorization.

16661720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 416554 (or 416550 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 29.

The square root of 16661720 is about 4081.8770192155. The cubic root of 16661720 is about 255.4112037818.

The spelling of 16661720 in words is "sixteen million, six hundred sixty-one thousand, seven hundred twenty".