21234356 has 24 divisors (see below), whose sum is σ = 43657824. Its totient is φ = 8909280.

The previous prime is 21234347. The next prime is 21234361. The reversal of 21234356 is 65343212.

It is a Smith number, since the sum of its digits (26) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17990 + ... + 19133.

It is an arithmetic number, because the mean of its divisors is an integer number (1819076).

Almost surely, 2^21234356 is an apocalyptic number.

21234356 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

21234356 is an abundant number, since it is smaller than the sum of its proper divisors (22423468).

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

21234356 is a wasteful number, since it uses less digits than its factorization.

21234356 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37151 (or 37149 counting only the distinct ones).

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

The square root of 21234356 is about 4608.0750861938. The cubic root of 21234356 is about 276.9149256306.

Adding to 21234356 its reverse (65343212), we get a palindrome (86577568).

The spelling of 21234356 in words is "twenty-one million, two hundred thirty-four thousand, three hundred fifty-six".