21115187638206 has 16 divisors (see below), whose sum is σ = 42231478270464. Its totient is φ = 7038212047064.

The previous prime is 21115187638187. The next prime is 21115187638231. The reversal of 21115187638206 is 60283678151112.

It is a super-2 number, since 2×21115187638206² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 45709116 + ... + 46168751.

It is an arithmetic number, because the mean of its divisors is an integer number (2639467391904).

Almost surely, 2^{21115187638206} is an apocalyptic number.

21115187638206 is an abundant number, since it is smaller than the sum of its proper divisors (21116290632258).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21115187638206 is a wasteful number, since it uses less digits than its factorization.

21115187638206 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91916175.

The product of its (nonzero) digits is 967680, while the sum is 51.

The spelling of 21115187638206 in words is "twenty-one trillion, one hundred fifteen billion, one hundred eighty-seven million, six hundred thirty-eight thousand, two hundred six".