21011110010101 has 4 divisors (see below), whose sum is σ = 22247057657772. Its totient is φ = 19775162362432.

The previous prime is 21011110010003. The next prime is 21011110010227. The reversal of 21011110010101 is 10101001111012.

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

It can be written as a sum of positive squares in 2 ways, for example, as 12361623128100 + 8649486882001 = 3515910^2 + 2941001^2 .

It is a cyclic number.

It is not a de Polignac number, because 21011110010101 - 2¹⁹ = 21011109485813 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21011110010701) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 617973823810 + ... + 617973823843.

It is an arithmetic number, because the mean of its divisors is an integer number (5561764414443).

Almost surely, 2^{21011110010101} is an apocalyptic number.

It is an amenable number.

21011110010101 is a deficient number, since it is larger than the sum of its proper divisors (1235947647671).

21011110010101 is a wasteful number, since it uses less digits than its factorization.

21011110010101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1235947647670.

The product of its (nonzero) digits is 2, while the sum is 10.

Adding to 21011110010101 its reverse (10101001111012), we get a palindrome (31112111121113).

The spelling of 21011110010101 in words is "twenty-one trillion, eleven billion, one hundred ten million, ten thousand, one hundred one".