21556115412107 has 4 divisors (see below), whose sum is σ = 21962834570880. Its totient is φ = 21149396253336.

The previous prime is 21556115412053. The next prime is 21556115412113. The reversal of 21556115412107 is 70121451165512.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21556115412107 - 2²⁴ = 21556098634891 is a prime.

It is a super-2 number, since 2×21556115412107² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21556115412137) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 203359579307 + ... + 203359579412.

It is an arithmetic number, because the mean of its divisors is an integer number (5490708642720).

Almost surely, 2^{21556115412107} is an apocalyptic number.

21556115412107 is a deficient number, since it is larger than the sum of its proper divisors (406719158773).

21556115412107 is an equidigital number, since it uses as much as digits as its factorization.

21556115412107 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 406719158772.

The product of its (nonzero) digits is 84000, while the sum is 41.

Adding to 21556115412107 its reverse (70121451165512), we get a palindrome (91677566577619).

The spelling of 21556115412107 in words is "twenty-one trillion, five hundred fifty-six billion, one hundred fifteen million, four hundred twelve thousand, one hundred seven".