21415145513 has 4 divisors (see below), whose sum is σ = 21435179460. Its totient is φ = 21395111568.

The previous prime is 21415145491. The next prime is 21415145561. The reversal of 21415145513 is 31554151412.

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 9180130969 + 12235014544 = 95813^2 + 110612^2 .

It is a cyclic number.

It is not a de Polignac number, because 21415145513 - 2⁶ = 21415145449 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21415145513.

It is not an unprimeable number, because it can be changed into a prime (21415145113) 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, 10015370 + ... + 10017507.

It is an arithmetic number, because the mean of its divisors is an integer number (5358794865).

Almost surely, 2^21415145513 is an apocalyptic number.

It is an amenable number.

21415145513 is a deficient number, since it is larger than the sum of its proper divisors (20033947).

21415145513 is a wasteful number, since it uses less digits than its factorization.

21415145513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20033946.

The product of its digits is 12000, while the sum is 32.

Adding to 21415145513 its reverse (31554151412), we get a palindrome (52969296925).

The spelling of 21415145513 in words is "twenty-one billion, four hundred fifteen million, one hundred forty-five thousand, five hundred thirteen".