21042451250540 has 48 divisors (see below), whose sum is σ = 45890782912800. Its totient is φ = 8095118180352.

The previous prime is 21042451250473. The next prime is 21042451250573. The reversal of 21042451250540 is 4505215424012.

It is a self number, because there is not a number n which added to its sum of digits gives 21042451250540.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 70434770 + ... + 70732889.

It is an arithmetic number, because the mean of its divisors is an integer number (956057977350).

Almost surely, 2^{21042451250540} is an apocalyptic number.

21042451250540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21042451250540 is an abundant number, since it is smaller than the sum of its proper divisors (24848331662260).

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

21042451250540 is a wasteful number, since it uses less digits than its factorization.

21042451250540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 141167954 (or 141167952 counting only the distinct ones).

The product of its (nonzero) digits is 64000, while the sum is 35.

Adding to 21042451250540 its reverse (4505215424012), we get a palindrome (25547666674552).

The spelling of 21042451250540 in words is "twenty-one trillion, forty-two billion, four hundred fifty-one million, two hundred fifty thousand, five hundred forty".