20761680 has 160 divisors (see below), whose sum is σ = 70531200. Its totient is φ = 5031936.

The previous prime is 20761669. The next prime is 20761693. The reversal of 20761680 is 8616702.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 132162 + ... + 132318.

It is an arithmetic number, because the mean of its divisors is an integer number (440820).

Almost surely, 2^20761680 is an apocalyptic number.

20761680 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 20761680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35265600).

20761680 is an abundant number, since it is smaller than the sum of its proper divisors (49769520).

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

20761680 is a wasteful number, since it uses less digits than its factorization.

20761680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221 (or 215 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 30.

The square root of 20761680 is about 4556.4986557663. The cubic root of 20761680 is about 274.8447829314.

The spelling of 20761680 in words is "twenty million, seven hundred sixty-one thousand, six hundred eighty".