21031434 has 32 divisors (see below), whose sum is σ = 47442240. Its totient is φ = 6904656.

The previous prime is 21031433. The next prime is 21031457. The reversal of 21031434 is 43413012.

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

It is not an unprimeable number, because it can be changed into a prime (21031433) 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, 712 + ... + 6524.

It is an arithmetic number, because the mean of its divisors is an integer number (1482570).

Almost surely, 2^21031434 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21031434, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23721120).

21031434 is an abundant number, since it is smaller than the sum of its proper divisors (26410806).

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

21031434 is a wasteful number, since it uses less digits than its factorization.

21031434 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5891 (or 5885 counting only the distinct ones).

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

The square root of 21031434 is about 4586.0041430422. The cubic root of 21031434 is about 276.0300061895.

Adding to 21031434 its reverse (43413012), we get a palindrome (64444446).

The spelling of 21031434 in words is "twenty-one million, thirty-one thousand, four hundred thirty-four".