20421360 has 120 divisors (see below), whose sum is σ = 69464304. Its totient is φ = 5376000.

The previous prime is 20421347. The next prime is 20421367. The reversal of 20421360 is 6312402.

It is a happy number.

It is a Cunningham number, because it is equal to 4519²-1.

It is a tau number, because it is divible by the number of its divisors (120).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20421367) 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, 81235 + ... + 81485.

Almost surely, 2^20421360 is an apocalyptic number.

20421360 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 20421360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34732152).

20421360 is an abundant number, since it is smaller than the sum of its proper divisors (49042944).

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

20421360 is a wasteful number, since it uses less digits than its factorization.

20421360 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 383 (or 374 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 20421360 is about 4518.9998893561. Note that the first 3 decimals coincide. The cubic root of 20421360 is about 273.3347742670.

Adding to 20421360 its reverse (6312402), we get a palindrome (26733762).

The spelling of 20421360 in words is "twenty million, four hundred twenty-one thousand, three hundred sixty".