21155003514461 has 4 divisors (see below), whose sum is σ = 21884486394300. Its totient is φ = 20425520634624.

The previous prime is 21155003514401. The next prime is 21155003514467. The reversal of 21155003514461 is 16441530055112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 17940222648100 + 3214780866361 = 4235590^2 + 1792981^2 .

It is a cyclic number.

It is not a de Polignac number, because 21155003514461 - 2⁶ = 21155003514397 is a prime.

It is a super-2 number, since 2×21155003514461² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21155003514467) 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, 364741439876 + ... + 364741439933.

It is an arithmetic number, because the mean of its divisors is an integer number (5471121598575).

Almost surely, 2^{21155003514461} is an apocalyptic number.

It is an amenable number.

21155003514461 is a deficient number, since it is larger than the sum of its proper divisors (729482879839).

21155003514461 is an equidigital number, since it uses as much as digits as its factorization.

21155003514461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 729482879838.

The product of its (nonzero) digits is 72000, while the sum is 38.

Adding to 21155003514461 its reverse (16441530055112), we get a palindrome (37596533569573).

The spelling of 21155003514461 in words is "twenty-one trillion, one hundred fifty-five billion, three million, five hundred fourteen thousand, four hundred sixty-one".