20857320 has 192 divisors, whose sum is σ = 77500800. Its totient is φ = 4815360.

The previous prime is 20857313. The next prime is 20857321. The reversal of 20857320 is 2375802.

It is not an unprimeable number, because it can be changed into a prime (20857321) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 90966 + ... + 91194.

It is an arithmetic number, because the mean of its divisors is an integer number (403650).

Almost surely, 2^20857320 is an apocalyptic number.

20857320 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 20857320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38750400).

20857320 is an abundant number, since it is smaller than the sum of its proper divisors (56643480).

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

20857320 is a wasteful number, since it uses less digits than its factorization.

20857320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 280 (or 273 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 27.

The square root of 20857320 is about 4566.9814976634. The cubic root of 20857320 is about 275.2661665425.

The spelling of 20857320 in words is "twenty million, eight hundred fifty-seven thousand, three hundred twenty".