20021520 has 40 divisors (see below), whose sum is σ = 62067456. Its totient is φ = 5339008.

The previous prime is 20021501. The next prime is 20021527. The reversal of 20021520 is 2512002.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×20021520² = 801722526220800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 20021496 and 20021505.

It is not an unprimeable number, because it can be changed into a prime (20021527) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 41472 + ... + 41951.

Almost surely, 2^20021520 is an apocalyptic number.

20021520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20021520 is an abundant number, since it is smaller than the sum of its proper divisors (42045936).

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

20021520 is a wasteful number, since it uses less digits than its factorization.

20021520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83439 (or 83433 counting only the distinct ones).

The product of its (nonzero) digits is 40, while the sum is 12.

The square root of 20021520 is about 4474.5413172749. The cubic root of 20021520 is about 271.5390838734.

Adding to 20021520 its reverse (2512002), we get a palindrome (22533522).

The spelling of 20021520 in words is "twenty million, twenty-one thousand, five hundred twenty".