21423356 has 24 divisors (see below), whose sum is σ = 38941056. Its totient is φ = 10301760.

The previous prime is 21423343. The next prime is 21423359. The reversal of 21423356 is 65332412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21423359) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23990 + ... + 24866.

It is an arithmetic number, because the mean of its divisors is an integer number (1622544).

Almost surely, 2^21423356 is an apocalyptic number.

It is an amenable number.

21423356 is a deficient number, since it is larger than the sum of its proper divisors (17517700).

21423356 is a wasteful number, since it uses less digits than its factorization.

21423356 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1109 (or 1107 counting only the distinct ones).

The product of its digits is 4320, while the sum is 26.

The square root of 21423356 is about 4628.5371339118. The cubic root of 21423356 is about 277.7340762302.

Adding to 21423356 its reverse (65332412), we get a palindrome (86755768).

The spelling of 21423356 in words is "twenty-one million, four hundred twenty-three thousand, three hundred fifty-six".