20513040 has 80 divisors (see below), whose sum is σ = 64186368. Its totient is φ = 5419008.

The previous prime is 20513039. The next prime is 20513057. The reversal of 20513040 is 4031502.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 30144 + ... + 30816.

Almost surely, 2^20513040 is an apocalyptic number.

20513040 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 20513040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32093184).

20513040 is an abundant number, since it is smaller than the sum of its proper divisors (43673328).

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

20513040 is a wasteful number, since it uses less digits than its factorization.

20513040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 816 (or 810 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 15.

The square root of 20513040 is about 4529.1323672421. The cubic root of 20513040 is about 273.7432015993.

Adding to 20513040 its reverse (4031502), we get a palindrome (24544542).

The spelling of 20513040 in words is "twenty million, five hundred thirteen thousand, forty".