21402000 has 240 divisors, whose sum is σ = 79213680. Its totient is φ = 5376000.

The previous prime is 21401993. The next prime is 21402013. The reversal of 21402000 is 20412.

It can be written as a sum of positive squares in 8 ways, for example, as 12616704 + 8785296 = 3552^2 + 2964^2 .

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (9).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 521980 + ... + 522020.

It is an arithmetic number, because the mean of its divisors is an integer number (330057).

Almost surely, 2^21402000 is an apocalyptic number.

21402000 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 21402000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39606840).

21402000 is an abundant number, since it is smaller than the sum of its proper divisors (57811680).

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

21402000 is a wasteful number, since it uses less digits than its factorization.

21402000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99 (or 80 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 9.

The square root of 21402000 is about 4626.2295662883. The cubic root of 21402000 is about 277.6417585917.

Adding to 21402000 its reverse (20412), we get a palindrome (21422412).

The spelling of 21402000 in words is "twenty-one million, four hundred two thousand".