21231234 has 40 divisors (see below), whose sum is σ = 48177360. Its totient is φ = 6987384.

The previous prime is 21231173. The next prime is 21231241. The reversal of 21231234 is 43213212.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 12657 + ... + 14235.

It is an arithmetic number, because the mean of its divisors is an integer number (1204434).

Almost surely, 2^21231234 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21231234, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24088680).

21231234 is an abundant number, since it is smaller than the sum of its proper divisors (26946126).

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

21231234 is a wasteful number, since it uses less digits than its factorization.

21231234 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1676 (or 1667 counting only the distinct ones).

The product of its digits is 288, while the sum is 18.

The square root of 21231234 is about 4607.7363205809. The cubic root of 21231234 is about 276.9013537447.

Adding to 21231234 its reverse (43213212), we get a palindrome (64444446).

The spelling of 21231234 in words is "twenty-one million, two hundred thirty-one thousand, two hundred thirty-four".