21250443400061 has 4 divisors (see below), whose sum is σ = 21357229548000. Its totient is φ = 21143657252124.

The previous prime is 21250443400031. The next prime is 21250443400073. The reversal of 21250443400061 is 16000434405212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21250443400061 is a prime.

It is a super-2 number, since 2×21250443400061² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21250443400031) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 53393073671 + ... + 53393074068.

It is an arithmetic number, because the mean of its divisors is an integer number (5339307387000).

Almost surely, 2^{21250443400061} is an apocalyptic number.

It is an amenable number.

21250443400061 is a deficient number, since it is larger than the sum of its proper divisors (106786147939).

21250443400061 is a wasteful number, since it uses less digits than its factorization.

21250443400061 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106786147938.

The product of its (nonzero) digits is 23040, while the sum is 32.

Adding to 21250443400061 its reverse (16000434405212), we get a palindrome (37250877805273).

The spelling of 21250443400061 in words is "twenty-one trillion, two hundred fifty billion, four hundred forty-three million, four hundred thousand, sixty-one".