21020420254 has 8 divisors (see below), whose sum is σ = 31742245800. Its totient is φ = 10439671656.

The previous prime is 21020420249. The next prime is 21020420261. The reversal of 21020420254 is 45202402012.

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

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 35268864 + ... + 35269459.

It is an arithmetic number, because the mean of its divisors is an integer number (3967780725).

Almost surely, 2^21020420254 is an apocalyptic number.

21020420254 is a deficient number, since it is larger than the sum of its proper divisors (10721825546).

21020420254 is a wasteful number, since it uses less digits than its factorization.

21020420254 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70538474.

The product of its (nonzero) digits is 1280, while the sum is 22.

Adding to 21020420254 its reverse (45202402012), we get a palindrome (66222822266).

The spelling of 21020420254 in words is "twenty-one billion, twenty million, four hundred twenty thousand, two hundred fifty-four".