21420242434 has 16 divisors (see below), whose sum is σ = 32285870496. Its totient is φ = 10658347200.

The previous prime is 21420242407. The next prime is 21420242449. The reversal of 21420242434 is 43424202412.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 723429 + ... + 752455.

It is an arithmetic number, because the mean of its divisors is an integer number (2017866906).

Almost surely, 2^21420242434 is an apocalyptic number.

21420242434 is a deficient number, since it is larger than the sum of its proper divisors (10865628062).

21420242434 is a wasteful number, since it uses less digits than its factorization.

21420242434 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30801.

The product of its (nonzero) digits is 12288, while the sum is 28.

Adding to 21420242434 its reverse (43424202412), we get a palindrome (64844444846).

The spelling of 21420242434 in words is "twenty-one billion, four hundred twenty million, two hundred forty-two thousand, four hundred thirty-four".