21515451442530 has 128 divisors (see below), whose sum is σ = 53832770553600. Its totient is φ = 5499753692160.

The previous prime is 21515451442483. The next prime is 21515451442559. The reversal of 21515451442530 is 3524415451512.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 13707109 + ... + 15195911.

It is an arithmetic number, because the mean of its divisors is an integer number (420568519950).

Almost surely, 2^{21515451442530} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21515451442530, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26916385276800).

21515451442530 is an abundant number, since it is smaller than the sum of its proper divisors (32317319111070).

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

21515451442530 is a wasteful number, since it uses less digits than its factorization.

21515451442530 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1489076.

The product of its (nonzero) digits is 480000, while the sum is 42.

The spelling of 21515451442530 in words is "twenty-one trillion, five hundred fifteen billion, four hundred fifty-one million, four hundred forty-two thousand, five hundred thirty".