20657320 has 16 divisors (see below), whose sum is σ = 46479060. Its totient is φ = 8262912.

The previous prime is 20657311. The next prime is 20657323. The reversal of 20657320 is 2375602.

It can be written as a sum of positive squares in 2 ways, for example, as 20629764 + 27556 = 4542^2 + 166^2 .

It is not an unprimeable number, because it can be changed into a prime (20657323) 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, 258177 + ... + 258256.

Almost surely, 2^20657320 is an apocalyptic number.

20657320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20657320 is an abundant number, since it is smaller than the sum of its proper divisors (25821740).

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

20657320 is a wasteful number, since it uses less digits than its factorization.

20657320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 516444 (or 516440 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 25.

The square root of 20657320 is about 4545.0324531295. The cubic root of 20657320 is about 274.3835004968.

The spelling of 20657320 in words is "twenty million, six hundred fifty-seven thousand, three hundred twenty".