21081234 has 32 divisors (see below), whose sum is σ = 43211520. Its totient is φ = 6854400.

The previous prime is 21081217. The next prime is 21081259. The reversal of 21081234 is 43218012.

It is a self number, because there is not a number n which added to its sum of digits gives 21081234.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 87354 + ... + 87594.

It is an arithmetic number, because the mean of its divisors is an integer number (1350360).

Almost surely, 2^21081234 is an apocalyptic number.

21081234 is an abundant number, since it is smaller than the sum of its proper divisors (22130286).

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

21081234 is a wasteful number, since it uses less digits than its factorization.

21081234 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 546.

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 21081234 is about 4591.4304960437. The cubic root of 21081234 is about 276.2477034814.

Adding to 21081234 its reverse (43218012), we get a palindrome (64299246).

The spelling of 21081234 in words is "twenty-one million, eighty-one thousand, two hundred thirty-four".