21387655678312 has 64 divisors (see below), whose sum is σ = 50492138279040. Its totient is φ = 8250349344000.

The previous prime is 21387655678307. The next prime is 21387655678313.

It is a happy number.

21387655678312 is nontrivially palindromic in base 10.

It is not an unprimeable number, because it can be changed into a prime (21387655678313) 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, 171820063 + ... + 171944494.

It is an arithmetic number, because the mean of its divisors is an integer number (788939660610).

Almost surely, 2^{21387655678312} is an apocalyptic number.

21387655678312 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21387655678312 is an abundant number, since it is smaller than the sum of its proper divisors (29104482600728).

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

21387655678312 is a wasteful number, since it uses less digits than its factorization.

21387655678312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 343764682 (or 343764678 counting only the distinct ones).

The product of its digits is 101606400, while the sum is 64.

The spelling of 21387655678312 in words is "twenty-one trillion, three hundred eighty-seven billion, six hundred fifty-five million, six hundred seventy-eight thousand, three hundred twelve".