21444143402525 has 18 divisors (see below), whose sum is σ = 26867695527630. Its totient is φ = 16978455621120.

The previous prime is 21444143402491. The next prime is 21444143402557. The reversal of 21444143402525 is 52520434144412.

It can be written as a sum of positive squares in 9 ways, for example, as 11296771378489 + 10147372024036 = 3361067^2 + 3185494^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21444143402525 is a prime.

It is a super-3 number, since 3×21444143402525³ (a number of 41 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 45346970 + ... + 45817419.

It is an arithmetic number, because the mean of its divisors is an integer number (1492649751535).

Almost surely, 2^{21444143402525} is an apocalyptic number.

21444143402525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21444143402525 is a deficient number, since it is larger than the sum of its proper divisors (5423552125105).

21444143402525 is an frugal number, since it uses more digits than its factorization.

21444143402525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91164593 (or 91164491 counting only the distinct ones).

The product of its (nonzero) digits is 614400, while the sum is 41.

Adding to 21444143402525 its reverse (52520434144412), we get a palindrome (73964577546937).

The spelling of 21444143402525 in words is "twenty-one trillion, four hundred forty-four billion, one hundred forty-three million, four hundred two thousand, five hundred twenty-five".