21042020402 has 64 divisors (see below), whose sum is σ = 38451127680. Its totient is φ = 8529878016.

The previous prime is 21042020401. The next prime is 21042020413. The reversal of 21042020402 is 20402024012.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is not an unprimeable number, because it can be changed into a prime (21042020401) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 543968 + ... + 581364.

It is an arithmetic number, because the mean of its divisors is an integer number (600798870).

Almost surely, 2^21042020402 is an apocalyptic number.

21042020402 is a deficient number, since it is larger than the sum of its proper divisors (17409107278).

21042020402 is a wasteful number, since it uses less digits than its factorization.

21042020402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37515.

The product of its (nonzero) digits is 256, while the sum is 17.

Adding to 21042020402 its reverse (20402024012), we get a palindrome (41444044414).

The spelling of 21042020402 in words is "twenty-one billion, forty-two million, twenty thousand, four hundred two".