21245220554 has 16 divisors (see below), whose sum is σ = 32490033120. Its totient is φ = 10415467920.

The previous prime is 21245220533. The next prime is 21245220593. The reversal of 21245220554 is 45502254212.

It is a self number, because there is not a number n which added to its sum of digits gives 21245220554.

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, 102737 + ... + 230315.

It is an arithmetic number, because the mean of its divisors is an integer number (2030627070).

Almost surely, 2^21245220554 is an apocalyptic number.

21245220554 is a deficient number, since it is larger than the sum of its proper divisors (11244812566).

21245220554 is a wasteful number, since it uses less digits than its factorization.

21245220554 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129205.

The product of its (nonzero) digits is 32000, while the sum is 32.

Adding to 21245220554 its reverse (45502254212), we get a palindrome (66747474766).

The spelling of 21245220554 in words is "twenty-one billion, two hundred forty-five million, two hundred twenty thousand, five hundred fifty-four".