21431434 has 4 divisors (see below), whose sum is σ = 32147154. Its totient is φ = 10715716.

The previous prime is 21431401. The next prime is 21431489. The reversal of 21431434 is 43413412.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 18020025 + 3411409 = 4245^2 + 1847^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5357857 + ... + 5357860.

Almost surely, 2^21431434 is an apocalyptic number.

21431434 is a deficient number, since it is larger than the sum of its proper divisors (10715720).

21431434 is a wasteful number, since it uses less digits than its factorization.

21431434 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10715719.

The product of its digits is 1152, while the sum is 22.

The square root of 21431434 is about 4629.4096815901. The cubic root of 21431434 is about 277.7689797865.

Adding to 21431434 its reverse (43413412), we get a palindrome (64844846).

The spelling of 21431434 in words is "twenty-one million, four hundred thirty-one thousand, four hundred thirty-four".