21842770849 has 3 divisors (see below), whose sum is σ = 21842918643. Its totient is φ = 21842623056.

The previous prime is 21842770723. The next prime is 21842770877. The reversal of 21842770849 is 94807724812.

The square root of 21842770849 is 147793.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 16634550625 + 5208220224 = 128975^2 + 72168^2 .

It is not a de Polignac number, because 21842770849 - 2⁷ = 21842770721 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21842770796 and 21842770805.

It is not an unprimeable number, because it can be changed into a prime (21842770949) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 73897 + ... + 221689.

It is an arithmetic number, because the mean of its divisors is an integer number (7280972881).

Almost surely, 2^21842770849 is an apocalyptic number.

21842770849 is the 147793-rd square number.

21842770849 is the 73897-th centered octagonal number.

It is an amenable number.

21842770849 is a deficient number, since it is larger than the sum of its proper divisors (147794).

21842770849 is an frugal number, since it uses more digits than its factorization.

21842770849 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 295586 (or 147793 counting only the distinct ones).

The product of its (nonzero) digits is 1806336, while the sum is 52.

The spelling of 21842770849 in words is "twenty-one billion, eight hundred forty-two million, seven hundred seventy thousand, eight hundred forty-nine".