21407946 has 64 divisors (see below), whose sum is σ = 52147200. Its totient is φ = 5723136.

The previous prime is 21407933. The next prime is 21407957. The reversal of 21407946 is 64970412.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 110826 + ... + 111018.

It is an arithmetic number, because the mean of its divisors is an integer number (814800).

Almost surely, 2^21407946 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21407946, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26073600).

21407946 is an abundant number, since it is smaller than the sum of its proper divisors (30739254).

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

21407946 is a wasteful number, since it uses less digits than its factorization.

21407946 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 363.

The product of its (nonzero) digits is 12096, while the sum is 33.

The square root of 21407946 is about 4626.8721616228. The cubic root of 21407946 is about 277.6674681054.

The spelling of 21407946 in words is "twenty-one million, four hundred seven thousand, nine hundred forty-six".