21654050247 has 16 divisors (see below), whose sum is σ = 32862516960. Its totient is φ = 14083934400.

The previous prime is 21654050227. The next prime is 21654050251. The reversal of 21654050247 is 74205045612.

It is a happy number.

21654050247 is a `hidden beast` number, since 2 + 1 + 6 + 5 + 405 + 0 + 247 = 666.

It is not a de Polignac number, because 21654050247 - 2¹⁸ = 21653788103 is a prime.

It is a super-2 number, since 2×21654050247² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21654050227) 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, 9779404 + ... + 9781617.

It is an arithmetic number, because the mean of its divisors is an integer number (2053907310).

Almost surely, 2^21654050247 is an apocalyptic number.

21654050247 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

21654050247 is a deficient number, since it is larger than the sum of its proper divisors (11208466713).

21654050247 is a wasteful number, since it uses less digits than its factorization.

21654050247 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19561071 (or 19561065 counting only the distinct ones).

The product of its (nonzero) digits is 67200, while the sum is 36.

Adding to 21654050247 its reverse (74205045612), we get a palindrome (95859095859).

The spelling of 21654050247 in words is "twenty-one billion, six hundred fifty-four million, fifty thousand, two hundred forty-seven".