20121340 has 24 divisors (see below), whose sum is σ = 43398432. Its totient is φ = 7830720.

The previous prime is 20121337. The next prime is 20121347. The reversal of 20121340 is 4312102.

It is a self number, because there is not a number n which added to its sum of digits gives 20121340.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20121347) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12856 + ... + 14335.

It is an arithmetic number, because the mean of its divisors is an integer number (1808268).

Almost surely, 2^20121340 is an apocalyptic number.

20121340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20121340 is an abundant number, since it is smaller than the sum of its proper divisors (23277092).

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

20121340 is a wasteful number, since it uses less digits than its factorization.

20121340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27237 (or 27235 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 20121340 is about 4485.6816650315. The cubic root of 20121340 is about 271.9896009577.

Adding to 20121340 its reverse (4312102), we get a palindrome (24433442).

The spelling of 20121340 in words is "twenty million, one hundred twenty-one thousand, three hundred forty".