20880021 has 8 divisors (see below), whose sum is σ = 29050560. Its totient is φ = 13314752.

The previous prime is 20880007. The next prime is 20880043. The reversal of 20880021 is 12008802.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20880021 - 2¹⁴ = 20863637 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20880021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20880001) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 151236 + ... + 151373.

It is an arithmetic number, because the mean of its divisors is an integer number (3631320).

Almost surely, 2^20880021 is an apocalyptic number.

It is an amenable number.

20880021 is a deficient number, since it is larger than the sum of its proper divisors (8170539).

20880021 is a wasteful number, since it uses less digits than its factorization.

20880021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 302635.

The product of its (nonzero) digits is 256, while the sum is 21.

The square root of 20880021 is about 4569.4661613803. The cubic root of 20880021 is about 275.3659964272.

Adding to 20880021 its reverse (12008802), we get a palindrome (32888823).

The spelling of 20880021 in words is "twenty million, eight hundred eighty thousand, twenty-one".