21851430 has 16 divisors (see below), whose sum is σ = 52443504. Its totient is φ = 5827040.

The previous prime is 21851419. The next prime is 21851441. The reversal of 21851430 is 3415812.

It is an interprime number because it is at equal distance from previous prime (21851419) and next prime (21851441).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21851430.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 364161 + ... + 364220.

It is an arithmetic number, because the mean of its divisors is an integer number (3277719).

Almost surely, 2^21851430 is an apocalyptic number.

21851430 is an abundant number, since it is smaller than the sum of its proper divisors (30592074).

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

21851430 is a wasteful number, since it uses less digits than its factorization.

21851430 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 728391.

The product of its (nonzero) digits is 960, while the sum is 24.

The square root of 21851430 is about 4674.5513153671. The cubic root of 21851430 is about 279.5717518090.

The spelling of 21851430 in words is "twenty-one million, eight hundred fifty-one thousand, four hundred thirty".