21501221545450 has 48 divisors (see below), whose sum is σ = 40042663668000. Its totient is φ = 8589656456640.

The previous prime is 21501221545423. The next prime is 21501221545663. The reversal of 21501221545450 is 5454512210512.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 188916661 + ... + 189030439.

It is an arithmetic number, because the mean of its divisors is an integer number (834222159750).

Almost surely, 2^{21501221545450} is an apocalyptic number.

21501221545450 is a deficient number, since it is larger than the sum of its proper divisors (18541442122550).

21501221545450 is a wasteful number, since it uses less digits than its factorization.

21501221545450 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 118519 (or 118514 counting only the distinct ones).

The product of its (nonzero) digits is 80000, while the sum is 37.

Adding to 21501221545450 its reverse (5454512210512), we get a palindrome (26955733755962).

The spelling of 21501221545450 in words is "twenty-one trillion, five hundred one billion, two hundred twenty-one million, five hundred forty-five thousand, four hundred fifty".