21135434 has 4 divisors (see below), whose sum is σ = 31703154. Its totient is φ = 10567716.

The previous prime is 21135431. The next prime is 21135449. The reversal of 21135434 is 43453112.

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., 21132409 + 3025 = 4597^2 + 55^2 .

It is not an unprimeable number, because it can be changed into a prime (21135431) by changing a digit.

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 as a sum of consecutive naturals, namely, 5283857 + ... + 5283860.

Almost surely, 2^21135434 is an apocalyptic number.

21135434 is a deficient number, since it is larger than the sum of its proper divisors (10567720).

21135434 is a wasteful number, since it uses less digits than its factorization.

21135434 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10567719.

The product of its digits is 1440, while the sum is 23.

The square root of 21135434 is about 4597.3290071519. The cubic root of 21135434 is about 276.4842458054.

Adding to 21135434 its reverse (43453112), we get a palindrome (64588546).

The spelling of 21135434 in words is "twenty-one million, one hundred thirty-five thousand, four hundred thirty-four".