21437430 has 128 divisors (see below), whose sum is σ = 63037440. Its totient is φ = 4561920.

The previous prime is 21437411. The next prime is 21437431. The reversal of 21437430 is 3473412.

It is a self number, because there is not a number n which added to its sum of digits gives 21437430.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21437431) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 240826 + ... + 240914.

It is an arithmetic number, because the mean of its divisors is an integer number (492480).

Almost surely, 2^21437430 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21437430, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31518720).

21437430 is an abundant number, since it is smaller than the sum of its proper divisors (41600010).

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

21437430 is a wasteful number, since it uses less digits than its factorization.

21437430 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 174.

The product of its (nonzero) digits is 2016, while the sum is 24.

The square root of 21437430 is about 4630.0572350674. The cubic root of 21437430 is about 277.7948817320.

The spelling of 21437430 in words is "twenty-one million, four hundred thirty-seven thousand, four hundred thirty".