21161016641 has 8 divisors (see below), whose sum is σ = 22261737600. Its totient is φ = 20085031120.

The previous prime is 21161016599. The next prime is 21161016649. The reversal of 21161016641 is 14661016112.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21161016641 - 2²⁶ = 21093907777 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21161016649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6182105 + ... + 6185526.

It is an arithmetic number, because the mean of its divisors is an integer number (2782717200).

Almost surely, 2^21161016641 is an apocalyptic number.

It is an amenable number.

21161016641 is a deficient number, since it is larger than the sum of its proper divisors (1100720959).

21161016641 is a wasteful number, since it uses less digits than its factorization.

21161016641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12367719.

The product of its (nonzero) digits is 1728, while the sum is 29.

The spelling of 21161016641 in words is "twenty-one billion, one hundred sixty-one million, sixteen thousand, six hundred forty-one".