21020402 has 32 divisors (see below), whose sum is σ = 35199360. Its totient is φ = 9354240.

The previous prime is 21020369. The next prime is 21020407. The reversal of 21020402 is 20402012.

It is not an unprimeable number, because it can be changed into a prime (21020407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 108818 + ... + 109010.

It is an arithmetic number, because the mean of its divisors is an integer number (1099980).

Almost surely, 2^21020402 is an apocalyptic number.

21020402 is a deficient number, since it is larger than the sum of its proper divisors (14178958).

21020402 is a wasteful number, since it uses less digits than its factorization.

21020402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 338.

The product of its (nonzero) digits is 32, while the sum is 11.

The square root of 21020402 is about 4584.8011952537. The cubic root of 21020402 is about 275.9817340709.

Adding to 21020402 its reverse (20402012), we get a palindrome (41422414).

The spelling of 21020402 in words is "twenty-one million, twenty thousand, four hundred two".