21250406562641 has 4 divisors (see below), whose sum is σ = 21254535265392. Its totient is φ = 21246277859892.

The previous prime is 21250406562629. The next prime is 21250406562643. The reversal of 21250406562641 is 14626560405212.

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-21250406562641 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21250406562592 and 21250406562601.

It is not an unprimeable number, because it can be changed into a prime (21250406562643) 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, 2064343655 + ... + 2064353948.

It is an arithmetic number, because the mean of its divisors is an integer number (5313633816348).

Almost surely, 2^{21250406562641} is an apocalyptic number.

It is an amenable number.

21250406562641 is a deficient number, since it is larger than the sum of its proper divisors (4128702751).

21250406562641 is an equidigital number, since it uses as much as digits as its factorization.

21250406562641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4128702750.

The product of its (nonzero) digits is 691200, while the sum is 44.

Adding to 21250406562641 its reverse (14626560405212), we get a palindrome (35876966967853).

The spelling of 21250406562641 in words is "twenty-one trillion, two hundred fifty billion, four hundred six million, five hundred sixty-two thousand, six hundred forty-one".