20657420 has 72 divisors (see below), whose sum is σ = 51193296. Its totient is φ = 6980736.

The previous prime is 20657419. The next prime is 20657423. The reversal of 20657420 is 2475602.

It is a self number, because there is not a number n which added to its sum of digits gives 20657420.

It is not an unprimeable number, because it can be changed into a prime (20657423) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 104762 + ... + 104958.

It is an arithmetic number, because the mean of its divisors is an integer number (711018).

Almost surely, 2^20657420 is an apocalyptic number.

20657420 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 20657420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25596648).

20657420 is an abundant number, since it is smaller than the sum of its proper divisors (30535876).

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

20657420 is a wasteful number, since it uses less digits than its factorization.

20657420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 327 (or 318 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 26.

The square root of 20657420 is about 4545.0434541377. The cubic root of 20657420 is about 274.3839432504.

The spelling of 20657420 in words is "twenty million, six hundred fifty-seven thousand, four hundred twenty".