21042434 has 8 divisors (see below), whose sum is σ = 36072768. Its totient is φ = 9018180.

The previous prime is 21042419. The next prime is 21042449. The reversal of 21042434 is 43424012.

It is an interprime number because it is at equal distance from previous prime (21042419) and next prime (21042449).

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 751502 + ... + 751529.

It is an arithmetic number, because the mean of its divisors is an integer number (4509096).

Almost surely, 2^21042434 is an apocalyptic number.

21042434 is a deficient number, since it is larger than the sum of its proper divisors (15030334).

21042434 is a wasteful number, since it uses less digits than its factorization.

21042434 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1503040.

The product of its (nonzero) digits is 768, while the sum is 20.

The square root of 21042434 is about 4587.2032874073. The cubic root of 21042434 is about 276.0781214830.

Adding to 21042434 its reverse (43424012), we get a palindrome (64466446).

The spelling of 21042434 in words is "twenty-one million, forty-two thousand, four hundred thirty-four".