20218849249 has 3 divisors (see below), whose sum is σ = 20218991443. Its totient is φ = 20218707056.

The previous prime is 20218849243. The next prime is 20218849289. The reversal of 20218849249 is 94294881202.

The square root of 20218849249 is 142193.

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., 20182464225 + 36385024 = 142065^2 + 6032^2 .

It is not a de Polignac number, because 20218849249 - 2³¹ = 18071365601 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20218849243) 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 2 ways as a sum of consecutive naturals, for example, 71097 + ... + 213289.

Almost surely, 2^20218849249 is an apocalyptic number.

20218849249 is the 142193-rd square number.

20218849249 is the 71097-th centered octagonal number.

It is an amenable number.

20218849249 is a deficient number, since it is larger than the sum of its proper divisors (142194).

20218849249 is an frugal number, since it uses more digits than its factorization.

20218849249 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 284386 (or 142193 counting only the distinct ones).

The product of its (nonzero) digits is 663552, while the sum is 49.

Multiplying 20218849249 by its sum of digits (49), we get a square (990723613201 = 995351²).

The spelling of 20218849249 in words is "twenty billion, two hundred eighteen million, eight hundred forty-nine thousand, two hundred forty-nine".