21996500 has 96 divisors (see below), whose sum is σ = 52284960. Its totient is φ = 8064000.

The previous prime is 21996493. The next prime is 21996503. The reversal of 21996500 is 569912.

It can be written as a sum of positive squares in 16 ways, for example, as 16370116 + 5626384 = 4046^2 + 2372^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21996503) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 536480 + ... + 536520.

It is an arithmetic number, because the mean of its divisors is an integer number (544635).

Almost surely, 2^21996500 is an apocalyptic number.

21996500 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 21996500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26142480).

21996500 is an abundant number, since it is smaller than the sum of its proper divisors (30288460).

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

21996500 is a wasteful number, since it uses less digits than its factorization.

21996500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126 (or 114 counting only the distinct ones).

The product of its (nonzero) digits is 4860, while the sum is 32.

The square root of 21996500 is about 4690.0426437294. The cubic root of 21996500 is about 280.1890729780.

The spelling of 21996500 in words is "twenty-one million, nine hundred ninety-six thousand, five hundred".