20161680 has 160 divisors (see below), whose sum is σ = 77995008. Its totient is φ = 4185600.

The previous prime is 20161667. The next prime is 20161693. The reversal of 20161680 is 8616102.

It is an interprime number because it is at equal distance from previous prime (20161667) and next prime (20161693).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 20161680.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 17935 + ... + 19025.

Almost surely, 2^20161680 is an apocalyptic number.

20161680 is a gapful number since it is divisible by the number (20) 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 20161680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38997504).

20161680 is an abundant number, since it is smaller than the sum of its proper divisors (57833328).

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

20161680 is a wasteful number, since it uses less digits than its factorization.

20161680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1125 (or 1119 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 24.

The square root of 20161680 is about 4490.1759431007. The cubic root of 20161680 is about 272.1712445305.

Adding to 20161680 its reverse (8616102), we get a palindrome (28777782).

The spelling of 20161680 in words is "twenty million, one hundred sixty-one thousand, six hundred eighty".