21956388471 has 16 divisors (see below), whose sum is σ = 34441394400. Its totient is φ = 13776557184.

The previous prime is 21956388469. The next prime is 21956388473. The reversal of 21956388471 is 17488365912.

21956388471 is a `hidden beast` number, since 2 + 1 + 9 + 563 + 8 + 8 + 4 + 71 = 666.

It is an interprime number because it is at equal distance from previous prime (21956388469) and next prime (21956388473).

It is not a de Polignac number, because 21956388471 - 2¹ = 21956388469 is a prime.

It is a super-3 number, since 3×21956388471³ (a number of 32 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21956388473) 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, 23917176 + ... + 23918093.

It is an arithmetic number, because the mean of its divisors is an integer number (2152587150).

Almost surely, 2^21956388471 is an apocalyptic number.

21956388471 is a deficient number, since it is larger than the sum of its proper divisors (12485005929).

21956388471 is a wasteful number, since it uses less digits than its factorization.

21956388471 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47835295 (or 47835289 counting only the distinct ones).

The product of its digits is 2903040, while the sum is 54.

The spelling of 21956388471 in words is "twenty-one billion, nine hundred fifty-six million, three hundred eighty-eight thousand, four hundred seventy-one".