21020007842 has 8 divisors (see below), whose sum is σ = 31756846800. Its totient is φ = 10434392244.

The previous prime is 21020007791. The next prime is 21020007847. The reversal of 21020007842 is 24870002012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (21020007847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 37805492 + ... + 37806047.

It is an arithmetic number, because the mean of its divisors is an integer number (3969605850).

Almost surely, 2^21020007842 is an apocalyptic number.

21020007842 is a deficient number, since it is larger than the sum of its proper divisors (10736838958).

21020007842 is a wasteful number, since it uses less digits than its factorization.

21020007842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75611680.

The product of its (nonzero) digits is 1792, while the sum is 26.

Adding to 21020007842 its reverse (24870002012), we get a palindrome (45890009854).

The spelling of 21020007842 in words is "twenty-one billion, twenty million, seven thousand, eight hundred forty-two".