21129000 has 64 divisors (see below), whose sum is σ = 65931840. Its totient is φ = 5633600.

The previous prime is 21128971. The next prime is 21129037. The reversal of 21129000 is 92112.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 522 + ... + 6521.

It is an arithmetic number, because the mean of its divisors is an integer number (1030185).

Almost surely, 2^21129000 is an apocalyptic number.

21129000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21129000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32965920).

21129000 is an abundant number, since it is smaller than the sum of its proper divisors (44802840).

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

21129000 is a wasteful number, since it uses less digits than its factorization.

21129000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7067 (or 7053 counting only the distinct ones).

The product of its (nonzero) digits is 36, while the sum is 15.

The square root of 21129000 is about 4596.6291997506. The cubic root of 21129000 is about 276.4561873929.

The spelling of 21129000 in words is "twenty-one million, one hundred twenty-nine thousand".