21520535321154 has 32 divisors (see below), whose sum is σ = 44262412721856. Its totient is φ = 6971316346880.

The previous prime is 21520535321071. The next prime is 21520535321167. The reversal of 21520535321154 is 45112353502512.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 170134932 + ... + 170261375.

It is an arithmetic number, because the mean of its divisors is an integer number (1383200397558).

Almost surely, 2^{21520535321154} is an apocalyptic number.

21520535321154 is an abundant number, since it is smaller than the sum of its proper divisors (22741877400702).

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

21520535321154 is a wasteful number, since it uses less digits than its factorization.

21520535321154 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 340396610.

The product of its (nonzero) digits is 180000, while the sum is 39.

Adding to 21520535321154 its reverse (45112353502512), we get a palindrome (66632888823666).

The spelling of 21520535321154 in words is "twenty-one trillion, five hundred twenty billion, five hundred thirty-five million, three hundred twenty-one thousand, one hundred fifty-four".