21147900 has 72 divisors (see below), whose sum is σ = 61714800. Its totient is φ = 5591040.

The previous prime is 21147869. The next prime is 21147937. The reversal of 21147900 is 974112.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 46876 + ... + 47324.

It is an arithmetic number, because the mean of its divisors is an integer number (857150).

Almost surely, 2^21147900 is an apocalyptic number.

21147900 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 21147900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30857400).

21147900 is an abundant number, since it is smaller than the sum of its proper divisors (40566900).

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

21147900 is a wasteful number, since it uses less digits than its factorization.

21147900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 623 (or 616 counting only the distinct ones).

The product of its (nonzero) digits is 504, while the sum is 24.

The square root of 21147900 is about 4598.6845945335. The cubic root of 21147900 is about 276.5385933244.

The spelling of 21147900 in words is "twenty-one million, one hundred forty-seven thousand, nine hundred".