20523420 has 144 divisors (see below), whose sum is σ = 69582240. Its totient is φ = 4866048.

The previous prime is 20523407. The next prime is 20523421. The reversal of 20523420 is 2432502.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 20523393 and 20523402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20523421) 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, 57964 + ... + 58316.

It is an arithmetic number, because the mean of its divisors is an integer number (483210).

Almost surely, 2^20523420 is an apocalyptic number.

20523420 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 20523420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34791120).

20523420 is an abundant number, since it is smaller than the sum of its proper divisors (49058820).

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

20523420 is a wasteful number, since it uses less digits than its factorization.

20523420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 404 (or 399 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 18.

The square root of 20523420 is about 4530.2781371567. The cubic root of 20523420 is about 273.7893669538.

Adding to 20523420 its reverse (2432502), we get a palindrome (22955922).

The spelling of 20523420 in words is "twenty million, five hundred twenty-three thousand, four hundred twenty".