20136840 has 64 divisors (see below), whose sum is σ = 63970560. Its totient is φ = 5053440.

The previous prime is 20136811. The next prime is 20136841. The reversal of 20136840 is 4863102.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 20136840.

It is not an unprimeable number, because it can be changed into a prime (20136841) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2896 + ... + 6975.

It is an arithmetic number, because the mean of its divisors is an integer number (999540).

Almost surely, 2^20136840 is an apocalyptic number.

20136840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20136840 is an abundant number, since it is smaller than the sum of its proper divisors (43833720).

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

20136840 is a wasteful number, since it uses less digits than its factorization.

20136840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9902 (or 9898 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 20136840 is about 4487.4090520032. The cubic root of 20136840 is about 272.0594232915.

Adding to 20136840 its reverse (4863102), we get a palindrome (24999942).

The spelling of 20136840 in words is "twenty million, one hundred thirty-six thousand, eight hundred forty".