21191019202 has 4 divisors (see below), whose sum is σ = 31786528806. Its totient is φ = 10595509600.

The previous prime is 21191019193. The next prime is 21191019209. The reversal of 21191019202 is 20291019112.

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., 20712678561 + 478340641 = 143919^2 + 21871^2 .

It is not an unprimeable number, because it can be changed into a prime (21191019209) 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 as a sum of consecutive naturals, namely, 5297754799 + ... + 5297754802.

Almost surely, 2^21191019202 is an apocalyptic number.

21191019202 is a deficient number, since it is larger than the sum of its proper divisors (10595509604).

21191019202 is a wasteful number, since it uses less digits than its factorization.

21191019202 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10595509603.

The product of its (nonzero) digits is 648, while the sum is 28.

The spelling of 21191019202 in words is "twenty-one billion, one hundred ninety-one million, nineteen thousand, two hundred two".