21115213101 has 6 divisors (see below), whose sum is σ = 30499752270. Its totient is φ = 14076808728.

The previous prime is 21115213079. The next prime is 21115213111. The reversal of 21115213101 is 10131251112.

21115213101 is a `hidden beast` number, since 2 + 111 + 521 + 31 + 0 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 21069974025 + 45239076 = 145155^2 + 6726^2 .

It is not a de Polignac number, because 21115213101 - 2⁶ = 21115213037 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21115213111) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1173067386 + ... + 1173067403.

It is an arithmetic number, because the mean of its divisors is an integer number (5083292045).

Almost surely, 2^21115213101 is an apocalyptic number.

It is an amenable number.

21115213101 is a deficient number, since it is larger than the sum of its proper divisors (9384539169).

21115213101 is a wasteful number, since it uses less digits than its factorization.

21115213101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2346134795 (or 2346134792 counting only the distinct ones).

The product of its (nonzero) digits is 60, while the sum is 18.

Adding to 21115213101 its reverse (10131251112), we get a palindrome (31246464213).

The spelling of 21115213101 in words is "twenty-one billion, one hundred fifteen million, two hundred thirteen thousand, one hundred one".