21000434 has 32 divisors (see below), whose sum is σ = 40817280. Its totient is φ = 7869312.

The previous prime is 21000433. The next prime is 21000461. The reversal of 21000434 is 43400012.

It is a Harshad number since it is a multiple of its sum of digits (14).

It is not an unprimeable number, because it can be changed into a prime (21000433) 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, 422 + ... + 6494.

It is an arithmetic number, because the mean of its divisors is an integer number (1275540).

Almost surely, 2^21000434 is an apocalyptic number.

21000434 is a deficient number, since it is larger than the sum of its proper divisors (19816846).

21000434 is a wasteful number, since it uses less digits than its factorization.

21000434 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6114.

The product of its (nonzero) digits is 96, while the sum is 14.

The square root of 21000434 is about 4582.6230479934. The cubic root of 21000434 is about 275.8943182172.

Adding to 21000434 its reverse (43400012), we get a palindrome (64400446).

The spelling of 21000434 in words is "twenty-one million, four hundred thirty-four", and thus it is an aban number.