21471928686 has 64 divisors (see below), whose sum is σ = 53157787200. Its totient is φ = 6378922368.

The previous prime is 21471928663. The next prime is 21471928721. The reversal of 21471928686 is 68682917412.

It is a happy number.

21471928686 is a `hidden beast` number, since 2 + 1 + 471 + 92 + 8 + 6 + 86 = 666.

It is a super-2 number, since 2×21471928686² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 507001 + ... + 547716.

It is an arithmetic number, because the mean of its divisors is an integer number (830590425).

Almost surely, 2^21471928686 is an apocalyptic number.

21471928686 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21471928686 is an abundant number, since it is smaller than the sum of its proper divisors (31685858514).

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

21471928686 is a wasteful number, since it uses less digits than its factorization.

21471928686 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1054770 (or 1054764 counting only the distinct ones).

The product of its digits is 2322432, while the sum is 54.

The spelling of 21471928686 in words is "twenty-one billion, four hundred seventy-one million, nine hundred twenty-eight thousand, six hundred eighty-six".