21521354010 has 96 divisors (see below), whose sum is σ = 55985878080. Its totient is φ = 5292278784.

The previous prime is 21521354009. The next prime is 21521354021. The reversal of 21521354010 is 1045312512.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 8247586 + ... + 8250194.

It is an arithmetic number, because the mean of its divisors is an integer number (583186230).

Almost surely, 2^21521354010 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21521354010, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27992939040).

21521354010 is an abundant number, since it is smaller than the sum of its proper divisors (34464524070).

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

21521354010 is a wasteful number, since it uses less digits than its factorization.

21521354010 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4272 (or 4259 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 24.

Adding to 21521354010 its reverse (1045312512), we get a palindrome (22566666522).

The spelling of 21521354010 in words is "twenty-one billion, five hundred twenty-one million, three hundred fifty-four thousand, ten".