21115187638207 has 16 divisors (see below), whose sum is σ = 24111890484192. Its totient is φ = 18317868641280.

The previous prime is 21115187638187. The next prime is 21115187638231. The reversal of 21115187638207 is 70283678151112.

It is not a de Polignac number, because 21115187638207 - 2⁷ = 21115187638079 is a prime.

It is a super-2 number, since 2×21115187638207² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21115187638247) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 68981758 + ... + 69287179.

It is an arithmetic number, because the mean of its divisors is an integer number (1506993155262).

Almost surely, 2^{21115187638207} is an apocalyptic number.

21115187638207 is a deficient number, since it is larger than the sum of its proper divisors (2996702845985).

21115187638207 is a wasteful number, since it uses less digits than its factorization.

21115187638207 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138269658.

The product of its (nonzero) digits is 1128960, while the sum is 52.

The spelling of 21115187638207 in words is "twenty-one trillion, one hundred fifteen billion, one hundred eighty-seven million, six hundred thirty-eight thousand, two hundred seven".