21020434 has 8 divisors (see below), whose sum is σ = 31550220. Its totient is φ = 10503696.

The previous prime is 21020431. The next prime is 21020437. The reversal of 21020434 is 43402012.

It is an interprime number because it is at equal distance from previous prime (21020431) and next prime (21020437).

It can be written as a sum of positive squares in 2 ways, for example, as 20385225 + 635209 = 4515^2 + 797^2 .

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

It is a super-3 number, since 3×21020434³ (a number of 23 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (21020431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4012 + ... + 7624.

Almost surely, 2^21020434 is an apocalyptic number.

21020434 is a deficient number, since it is larger than the sum of its proper divisors (10529786).

21020434 is a wasteful number, since it uses less digits than its factorization.

21020434 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6524.

The product of its (nonzero) digits is 192, while the sum is 16.

The square root of 21020434 is about 4584.8046850438. The cubic root of 21020434 is about 275.9818741159.

Adding to 21020434 its reverse (43402012), we get a palindrome (64422446).

The spelling of 21020434 in words is "twenty-one million, twenty thousand, four hundred thirty-four".