20291680 has 24 divisors (see below), whose sum is σ = 47939472. Its totient is φ = 8116608.

The previous prime is 20291671. The next prime is 20291683. The reversal of 20291680 is 8619202.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20291683) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 63252 + ... + 63571.

It is an arithmetic number, because the mean of its divisors is an integer number (1997478).

Almost surely, 2^20291680 is an apocalyptic number.

20291680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20291680 is an abundant number, since it is smaller than the sum of its proper divisors (27647792).

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

20291680 is a wasteful number, since it uses less digits than its factorization.

20291680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 126838 (or 126830 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 20291680 is about 4504.6287305393. The cubic root of 20291680 is about 272.7549671540.

The spelling of 20291680 in words is "twenty million, two hundred ninety-one thousand, six hundred eighty".