21105402 has 16 divisors (see below), whose sum is σ = 42841632. Its totient is φ = 6930000.

The previous prime is 21105401. The next prime is 21105407. The reversal of 21105402 is 20450112.

It is not an unprimeable number, because it can be changed into a prime (21105401) 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 7 ways as a sum of consecutive naturals, for example, 25849 + ... + 26652.

It is an arithmetic number, because the mean of its divisors is an integer number (2677602).

Almost surely, 2^21105402 is an apocalyptic number.

21105402 is an abundant number, since it is smaller than the sum of its proper divisors (21736230).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21105402 is a wasteful number, since it uses less digits than its factorization.

21105402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52573.

The product of its (nonzero) digits is 80, while the sum is 15.

The square root of 21105402 is about 4594.0616016767. The cubic root of 21105402 is about 276.3532286895.

Adding to 21105402 its reverse (20450112), we get a palindrome (41555514).

The spelling of 21105402 in words is "twenty-one million, one hundred five thousand, four hundred two".