21234816 has 48 divisors (see below), whose sum is σ = 61108710. Its totient is φ = 7077888.

The previous prime is 21234809. The next prime is 21234817. The reversal of 21234816 is 61843212.

21234816 = 191³ + 192³ + 193³.

It can be written as a sum of positive squares in only one way, i.e., 17640000 + 3594816 = 4200^2 + 1896^2 .

It is a tau number, because it is divible by the number of its divisors (48).

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 21234816.

It is not an unprimeable number, because it can be changed into a prime (21234817) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8065 + ... + 10368.

Almost surely, 2^21234816 is an apocalyptic number.

It is an amenable number.

21234816 is an abundant number, since it is smaller than the sum of its proper divisors (39873894).

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

21234816 is a wasteful number, since it uses less digits than its factorization.

21234816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18453 (or 18438 counting only the distinct ones).

The product of its digits is 2304, while the sum is 27.

The square root of 21234816 is about 4608.1249983046. The cubic root of 21234816 is about 276.9169252195.

The spelling of 21234816 in words is "twenty-one million, two hundred thirty-four thousand, eight hundred sixteen".