21960000 has 210 divisors, whose sum is σ = 79944722. Its totient is φ = 5760000.

The previous prime is 21959957. The next prime is 21960007. The reversal of 21960000 is 6912.

It can be written as a sum of positive squares in 5 ways, for example, as 15116544 + 6843456 = 3888^2 + 2616^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21960007) by changing a digit.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 359970 + ... + 360030.

Almost surely, 2^21960000 is an apocalyptic number.

21960000 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 21960000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39972361).

21960000 is an abundant number, since it is smaller than the sum of its proper divisors (57984722).

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

21960000 is an equidigital number, since it uses as much as digits as its factorization.

21960000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99 (or 71 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 18.

The square root of 21960000 is about 4686.1498055440. The cubic root of 21960000 is about 280.0340094744.

Adding to 21960000 its reverse (6912), we get a palindrome (21966912).

The spelling of 21960000 in words is "twenty-one million, nine hundred sixty thousand".