21013035550 has 24 divisors (see below), whose sum is σ = 42090727896. Its totient is φ = 7758659040.

The previous prime is 21013035493. The next prime is 21013035569. The reversal of 21013035550 is 5553031012.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 16163224 + ... + 16164523.

It is an arithmetic number, because the mean of its divisors is an integer number (1753780329).

Almost surely, 2^21013035550 is an apocalyptic number.

21013035550 is an abundant number, since it is smaller than the sum of its proper divisors (21077692346).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21013035550 is a wasteful number, since it uses less digits than its factorization.

21013035550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32327772 (or 32327767 counting only the distinct ones).

The product of its (nonzero) digits is 2250, while the sum is 25.

Adding to 21013035550 its reverse (5553031012), we get a palindrome (26566066562).

The spelling of 21013035550 in words is "twenty-one billion, thirteen million, thirty-five thousand, five hundred fifty".