21021001442 has 16 divisors (see below), whose sum is σ = 36073838592. Its totient is φ = 8999541600.

The previous prime is 21021001439. The next prime is 21021001471. The reversal of 21021001442 is 24410012012.

It is a self number, because there is not a number n which added to its sum of digits gives 21021001442.

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, 774434 + ... + 801117.

It is an arithmetic number, because the mean of its divisors is an integer number (2254614912).

Almost surely, 2^21021001442 is an apocalyptic number.

21021001442 is a deficient number, since it is larger than the sum of its proper divisors (15052837150).

21021001442 is a wasteful number, since it uses less digits than its factorization.

21021001442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1576513.

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 21021001442 its reverse (24410012012), we get a palindrome (45431013454).

The spelling of 21021001442 in words is "twenty-one billion, twenty-one million, one thousand, four hundred forty-two".