21447426 has 64 divisors (see below), whose sum is σ = 57609216. Its totient is φ = 5140800.

The previous prime is 21447407. The next prime is 21447427. The reversal of 21447426 is 62474412.

It is a junction number, because it is equal to n+sod(n) for n = 21447393 and 21447402.

It is not an unprimeable number, because it can be changed into a prime (21447427) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4221 + ... + 7791.

It is an arithmetic number, because the mean of its divisors is an integer number (900144).

Almost surely, 2^21447426 is an apocalyptic number.

21447426 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 21447426, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28804608).

21447426 is an abundant number, since it is smaller than the sum of its proper divisors (36161790).

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

21447426 is a wasteful number, since it uses less digits than its factorization.

21447426 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3607.

The product of its digits is 10752, while the sum is 30.

The square root of 21447426 is about 4631.1365775585. The cubic root of 21447426 is about 277.8380524253.

The spelling of 21447426 in words is "twenty-one million, four hundred forty-seven thousand, four hundred twenty-six".