21415438 has 16 divisors (see below), whose sum is σ = 36567936. Its totient is φ = 9310840.

The previous prime is 21415423. The next prime is 21415439. The reversal of 21415438 is 83451412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21415439) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 20656 + ... + 21667.

It is an arithmetic number, because the mean of its divisors is an integer number (2285496).

Almost surely, 2^21415438 is an apocalyptic number.

21415438 is a deficient number, since it is larger than the sum of its proper divisors (15152498).

21415438 is a wasteful number, since it uses less digits than its factorization.

21415438 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42359.

The product of its digits is 3840, while the sum is 28.

The square root of 21415438 is about 4627.6817090202. The cubic root of 21415438 is about 277.6998554884.

The spelling of 21415438 in words is "twenty-one million, four hundred fifteen thousand, four hundred thirty-eight".