21504292849 has 4 divisors (see below), whose sum is σ = 23158469236. Its totient is φ = 19850116464.

The previous prime is 21504292847. The next prime is 21504292867. The reversal of 21504292849 is 94829240512.

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

It can be written as a sum of positive squares in 2 ways, for example, as 8453515249 + 13050777600 = 91943^2 + 114240^2 .

It is a cyclic number.

It is not a de Polignac number, because 21504292849 - 2¹ = 21504292847 is a prime.

It is a super-2 number, since 2×21504292849² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21504292799 and 21504292808.

It is not an unprimeable number, because it can be changed into a prime (21504292847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 827088174 + ... + 827088199.

It is an arithmetic number, because the mean of its divisors is an integer number (5789617309).

Almost surely, 2^21504292849 is an apocalyptic number.

It is an amenable number.

21504292849 is a deficient number, since it is larger than the sum of its proper divisors (1654176387).

21504292849 is a wasteful number, since it uses less digits than its factorization.

21504292849 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1654176386.

The product of its (nonzero) digits is 414720, while the sum is 46.

The spelling of 21504292849 in words is "twenty-one billion, five hundred four million, two hundred ninety-two thousand, eight hundred forty-nine".