21155011102 has 4 divisors (see below), whose sum is σ = 31732516656. Its totient is φ = 10577505550.

The previous prime is 21155011067. The next prime is 21155011153. The reversal of 21155011102 is 20111055112.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21155011102.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5288752774 + ... + 5288752777.

It is an arithmetic number, because the mean of its divisors is an integer number (7933129164).

Almost surely, 2^21155011102 is an apocalyptic number.

21155011102 is a deficient number, since it is larger than the sum of its proper divisors (10577505554).

21155011102 is a wasteful number, since it uses less digits than its factorization.

21155011102 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10577505553.

The product of its (nonzero) digits is 100, while the sum is 19.

Adding to 21155011102 its reverse (20111055112), we get a palindrome (41266066214).

The spelling of 21155011102 in words is "twenty-one billion, one hundred fifty-five million, eleven thousand, one hundred two".