21210421402 has 16 divisors (see below), whose sum is σ = 33605713152. Its totient is φ = 10024428960.

The previous prime is 21210421381. The next prime is 21210421429. The reversal of 21210421402 is 20412401212.

It is a self number, because there is not a number n which added to its sum of digits gives 21210421402.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3975283 + ... + 3980614.

It is an arithmetic number, because the mean of its divisors is an integer number (2100357072).

Almost surely, 2^21210421402 is an apocalyptic number.

21210421402 is a deficient number, since it is larger than the sum of its proper divisors (12395291750).

21210421402 is a wasteful number, since it uses less digits than its factorization.

21210421402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7955973.

The product of its (nonzero) digits is 256, while the sum is 19.

Adding to 21210421402 its reverse (20412401212), we get a palindrome (41622822614).

The spelling of 21210421402 in words is "twenty-one billion, two hundred ten million, four hundred twenty-one thousand, four hundred two".