21436858 has 16 divisors (see below), whose sum is σ = 33516000. Its totient is φ = 10270512.

The previous prime is 21436853. The next prime is 21436871. The reversal of 21436858 is 85863412.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21436853) by changing a digit.

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, 6733 + ... + 9391.

It is an arithmetic number, because the mean of its divisors is an integer number (2094750).

Almost surely, 2^21436858 is an apocalyptic number.

21436858 is a deficient number, since it is larger than the sum of its proper divisors (12079142).

21436858 is a wasteful number, since it uses less digits than its factorization.

21436858 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2829.

The product of its digits is 46080, while the sum is 37.

The square root of 21436858 is about 4629.9954643606. The cubic root of 21436858 is about 277.7924109743.

The spelling of 21436858 in words is "twenty-one million, four hundred thirty-six thousand, eight hundred fifty-eight".