21003892 has 48 divisors (see below), whose sum is σ = 47635840. Its totient is φ = 7869312.

The previous prime is 21003887. The next prime is 21003893. The reversal of 21003892 is 29830012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21003893) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5398 + ... + 8434.

Almost surely, 2^21003892 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 21003892, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23817920).

21003892 is an abundant number, since it is smaller than the sum of its proper divisors (26631948).

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

21003892 is a wasteful number, since it uses less digits than its factorization.

21003892 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3080 (or 3078 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 21003892 is about 4583.0003272965. Note that the first 3 decimals coincide. The cubic root of 21003892 is about 275.9094606057.

The spelling of 21003892 in words is "twenty-one million, three thousand, eight hundred ninety-two".