16721660 has 24 divisors (see below), whose sum is σ = 35864640. Its totient is φ = 6545984.

The previous prime is 16721657. The next prime is 16721671. The reversal of 16721660 is 6612761.

It is a super-2 number, since 2×16721660² = 559227826311200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7955 + ... + 9834.

It is an arithmetic number, because the mean of its divisors is an integer number (1494360).

Almost surely, 2^16721660 is an apocalyptic number.

16721660 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

16721660 is an abundant number, since it is smaller than the sum of its proper divisors (19142980).

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

16721660 is a wasteful number, since it uses less digits than its factorization.

16721660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17845 (or 17843 counting only the distinct ones).

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

The square root of 16721660 is about 4089.2126381493. The cubic root of 16721660 is about 255.7171150935.

It can be divided in two parts, 167216 and 60, that multiplied together give a triangular number (10032960 = T₄₄₇₉).

The spelling of 16721660 in words is "sixteen million, seven hundred twenty-one thousand, six hundred sixty".