21053434 has 4 divisors (see below), whose sum is σ = 31580154. Its totient is φ = 10526716.

The previous prime is 21053411. The next prime is 21053437. The reversal of 21053434 is 43435012.

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., 20675209 + 378225 = 4547^2 + 615^2 .

It is not an unprimeable number, because it can be changed into a prime (21053437) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5263357 + ... + 5263360.

Almost surely, 2^21053434 is an apocalyptic number.

21053434 is a deficient number, since it is larger than the sum of its proper divisors (10526720).

21053434 is a wasteful number, since it uses less digits than its factorization.

21053434 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10526719.

The product of its (nonzero) digits is 1440, while the sum is 22.

The square root of 21053434 is about 4588.4021183850. The cubic root of 21053434 is about 276.1262200112.

Adding to 21053434 its reverse (43435012), we get a palindrome (64488446).

The spelling of 21053434 in words is "twenty-one million, fifty-three thousand, four hundred thirty-four".