21161016651 has 8 divisors (see below), whose sum is σ = 28306594624. Its totient is φ = 14061391560.

The previous prime is 21161016649. The next prime is 21161016691. The reversal of 21161016651 is 15661016112.

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

It is not a de Polignac number, because 21161016651 - 2¹ = 21161016649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21161016691) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11487145 + ... + 11488986.

It is an arithmetic number, because the mean of its divisors is an integer number (3538324328).

Almost surely, 2^21161016651 is an apocalyptic number.

21161016651 is a deficient number, since it is larger than the sum of its proper divisors (7145577973).

21161016651 is a wasteful number, since it uses less digits than its factorization.

21161016651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22976441.

The product of its (nonzero) digits is 2160, while the sum is 30.

The spelling of 21161016651 in words is "twenty-one billion, one hundred sixty-one million, sixteen thousand, six hundred fifty-one".