20561361202 has 4 divisors (see below), whose sum is σ = 30842041806. Its totient is φ = 10280680600.

The previous prime is 20561361179. The next prime is 20561361217. The reversal of 20561361202 is 20216316502.

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

It can be written as a sum of positive squares in only one way, i.e., 13186158561 + 7375202641 = 114831^2 + 85879^2 .

It is a super-2 number, since 2×20561361202² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 5140340299 + ... + 5140340302.

Almost surely, 2^20561361202 is an apocalyptic number.

20561361202 is a deficient number, since it is larger than the sum of its proper divisors (10280680604).

20561361202 is a wasteful number, since it uses less digits than its factorization.

20561361202 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10280680603.

The product of its (nonzero) digits is 4320, while the sum is 28.

Adding to 20561361202 its reverse (20216316502), we get a palindrome (40777677704).

It can be divided in two parts, 205613 and 61202, that added together give a triangular number (266815 = T₇₃₀).

The spelling of 20561361202 in words is "twenty billion, five hundred sixty-one million, three hundred sixty-one thousand, two hundred two".