21116034325661 has 4 divisors (see below), whose sum is σ = 23035673809824. Its totient is φ = 19196394841500.

The previous prime is 21116034325649. The next prime is 21116034325667. The reversal of 21116034325661 is 16652343061112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21116034325661 - 2²⁶ = 21115967216797 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 (21116034325667) 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, 959819742065 + ... + 959819742086.

It is an arithmetic number, because the mean of its divisors is an integer number (5758918452456).

Almost surely, 2^{21116034325661} is an apocalyptic number.

It is an amenable number.

21116034325661 is a deficient number, since it is larger than the sum of its proper divisors (1919639484163).

21116034325661 is a wasteful number, since it uses less digits than its factorization.

21116034325661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1919639484162.

The product of its (nonzero) digits is 155520, while the sum is 41.

Adding to 21116034325661 its reverse (16652343061112), we get a palindrome (37768377386773).

The spelling of 21116034325661 in words is "twenty-one trillion, one hundred sixteen billion, thirty-four million, three hundred twenty-five thousand, six hundred sixty-one".