21202102775 has 36 divisors (see below), whose sum is σ = 31160083752. Its totient is φ = 14264228160.

The previous prime is 21202102771. The next prime is 21202102777. The reversal of 21202102775 is 57720120212.

It is not a de Polignac number, because 21202102775 - 2² = 21202102771 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21202102771) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 98357 + ... + 228206.

It is an arithmetic number, because the mean of its divisors is an integer number (865557882).

Almost surely, 2^21202102775 is an apocalyptic number.

21202102775 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21202102775 is a deficient number, since it is larger than the sum of its proper divisors (9957980977).

21202102775 is a wasteful number, since it uses less digits than its factorization.

21202102775 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 326640 (or 326628 counting only the distinct ones).

The product of its (nonzero) digits is 3920, while the sum is 29.

Adding to 21202102775 its reverse (57720120212), we get a palindrome (78922222987).

The spelling of 21202102775 in words is "twenty-one billion, two hundred two million, one hundred two thousand, seven hundred seventy-five".