21115244013 has 16 divisors (see below), whose sum is σ = 28579516416. Its totient is φ = 13864308080.

The previous prime is 21115243999. The next prime is 21115244021. The reversal of 21115244013 is 31044251112.

It is a cyclic number.

It is not a de Polignac number, because 21115244013 - 2¹³ = 21115235821 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21115244023) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 158956 + ... + 259802.

It is an arithmetic number, because the mean of its divisors is an integer number (1786219776).

Almost surely, 2^21115244013 is an apocalyptic number.

It is an amenable number.

21115244013 is a deficient number, since it is larger than the sum of its proper divisors (7464272403).

21115244013 is a wasteful number, since it uses less digits than its factorization.

21115244013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101904.

The product of its (nonzero) digits is 960, while the sum is 24.

Adding to 21115244013 its reverse (31044251112), we get a palindrome (52159495125).

The spelling of 21115244013 in words is "twenty-one billion, one hundred fifteen million, two hundred forty-four thousand, thirteen".