20021508 has 72 divisors (see below), whose sum is σ = 55036800. Its totient is φ = 6100416.

The previous prime is 20021501. The next prime is 20021527. The reversal of 20021508 is 80512002.

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

It is not an unprimeable number, because it can be changed into a prime (20021501) 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 23 ways as a sum of consecutive naturals, for example, 83653 + ... + 83891.

It is an arithmetic number, because the mean of its divisors is an integer number (764400).

Almost surely, 2^20021508 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20021508, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27518400).

20021508 is an abundant number, since it is smaller than the sum of its proper divisors (35015292).

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

20021508 is a wasteful number, since it uses less digits than its factorization.

20021508 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 441 (or 436 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

The square root of 20021508 is about 4474.5399763551. The cubic root of 20021508 is about 271.5390296240.

The spelling of 20021508 in words is "twenty million, twenty-one thousand, five hundred eight".