21203988 has 96 divisors (see below), whose sum is σ = 56918400. Its totient is φ = 6096384.

The previous prime is 21203977. The next prime is 21204013. The reversal of 21203988 is 88930212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 194478 + ... + 194586.

It is an arithmetic number, because the mean of its divisors is an integer number (592900).

Almost surely, 2^21203988 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 21203988, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28459200).

21203988 is an abundant number, since it is smaller than the sum of its proper divisors (35714412).

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

21203988 is a wasteful number, since it uses less digits than its factorization.

21203988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 201 (or 199 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 33.

The square root of 21203988 is about 4604.7788220500. The cubic root of 21203988 is about 276.7828540562.

The spelling of 21203988 in words is "twenty-one million, two hundred three thousand, nine hundred eighty-eight".