16666820 has 24 divisors (see below), whose sum is σ = 35209944. Its totient is φ = 6626816.

The previous prime is 16666807. The next prime is 16666823. The reversal of 16666820 is 2866661.

16666820 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 1674436 + 14992384 = 1294^2 + 3872^2 .

It is not an unprimeable number, because it can be changed into a prime (16666823) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1052 + ... + 5868.

It is an arithmetic number, because the mean of its divisors is an integer number (1467081).

Almost surely, 2^16666820 is an apocalyptic number.

16666820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

16666820 is an abundant number, since it is smaller than the sum of its proper divisors (18543124).

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

16666820 is a wasteful number, since it uses less digits than its factorization.

16666820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4999 (or 4997 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 35.

The square root of 16666820 is about 4082.5016840168. The cubic root of 16666820 is about 255.4372608006.

The spelling of 16666820 in words is "sixteen million, six hundred sixty-six thousand, eight hundred twenty".