21261234 has 32 divisors (see below), whose sum is σ = 44634240. Its totient is φ = 6742400.

The previous prime is 21261217. The next prime is 21261239. The reversal of 21261234 is 43216212.

It is a self number, because there is not a number n which added to its sum of digits gives 21261234.

It is not an unprimeable number, because it can be changed into a prime (21261239) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11494 + ... + 13214.

It is an arithmetic number, because the mean of its divisors is an integer number (1394820).

Almost surely, 2^21261234 is an apocalyptic number.

21261234 is an abundant number, since it is smaller than the sum of its proper divisors (23373006).

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

21261234 is a wasteful number, since it uses less digits than its factorization.

21261234 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1826.

The product of its digits is 576, while the sum is 21.

The square root of 21261234 is about 4610.9905660281. The cubic root of 21261234 is about 277.0317140593.

Adding to 21261234 its reverse (43216212), we get a palindrome (64477446).

The spelling of 21261234 in words is "twenty-one million, two hundred sixty-one thousand, two hundred thirty-four".