21956430 has 16 divisors (see below), whose sum is σ = 52695504. Its totient is φ = 5855040.

The previous prime is 21956423. The next prime is 21956461. The reversal of 21956430 is 3465912.

It is a Harshad number since it is a multiple of its sum of digits (30), and also a Moran number because the ratio is a prime number: 731881 = 21956430 / (2 + 1 + 9 + 5 + 6 + 4 + 3 + 0).

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, 365911 + ... + 365970.

It is an arithmetic number, because the mean of its divisors is an integer number (3293469).

Almost surely, 2^21956430 is an apocalyptic number.

21956430 is an abundant number, since it is smaller than the sum of its proper divisors (30739074).

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

21956430 is a wasteful number, since it uses less digits than its factorization.

21956430 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 731891.

The product of its (nonzero) digits is 6480, while the sum is 30.

The square root of 21956430 is about 4685.7688803440. The cubic root of 21956430 is about 280.0188337672.

The spelling of 21956430 in words is "twenty-one million, nine hundred fifty-six thousand, four hundred thirty".