21423786 has 32 divisors (see below), whose sum is σ = 43917120. Its totient is φ = 6965376.

The previous prime is 21423781. The next prime is 21423793. The reversal of 21423786 is 68732412.

It is not an unprimeable number, because it can be changed into a prime (21423781) 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 15 ways as a sum of consecutive naturals, for example, 54880 + ... + 55268.

It is an arithmetic number, because the mean of its divisors is an integer number (1372410).

Almost surely, 2^21423786 is an apocalyptic number.

21423786 is an abundant number, since it is smaller than the sum of its proper divisors (22493334).

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

21423786 is a wasteful number, since it uses less digits than its factorization.

21423786 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 598.

The product of its digits is 16128, while the sum is 33.

The square root of 21423786 is about 4628.5835846401. The cubic root of 21423786 is about 277.7359344024.

The spelling of 21423786 in words is "twenty-one million, four hundred twenty-three thousand, seven hundred eighty-six".