21500220115 has 16 divisors (see below), whose sum is σ = 28502023680. Its totient is φ = 15438589920.

The previous prime is 21500220113. The next prime is 21500220121. The reversal of 21500220115 is 51102200512.

It is not a de Polignac number, because 21500220115 - 2¹ = 21500220113 is a prime.

It is a super-2 number, since 2×21500220115² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21500220092 and 21500220101.

It is not an unprimeable number, because it can be changed into a prime (21500220113) 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, 2469789 + ... + 2478478.

It is an arithmetic number, because the mean of its divisors is an integer number (1781376480).

Almost surely, 2^21500220115 is an apocalyptic number.

21500220115 is a deficient number, since it is larger than the sum of its proper divisors (7001803565).

21500220115 is a wasteful number, since it uses less digits than its factorization.

21500220115 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4948362.

The product of its (nonzero) digits is 200, while the sum is 19.

Adding to 21500220115 its reverse (51102200512), we get a palindrome (72602420627).

The spelling of 21500220115 in words is "twenty-one billion, five hundred million, two hundred twenty thousand, one hundred fifteen".