21716126421 has 16 divisors (see below), whose sum is σ = 32259161088. Its totient is φ = 12881260400.

The previous prime is 21716126389. The next prime is 21716126423. The reversal of 21716126421 is 12462161712.

It is a cyclic number.

It is not a de Polignac number, because 21716126421 - 2⁵ = 21716126389 is a prime.

It is a super-3 number, since 3×21716126421³ (a number of 32 digits) contains 333 as substring.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21716126423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6999135 + ... + 7002236.

It is an arithmetic number, because the mean of its divisors is an integer number (2016197568).

Almost surely, 2^21716126421 is an apocalyptic number.

It is an amenable number.

21716126421 is a deficient number, since it is larger than the sum of its proper divisors (10543034667).

21716126421 is a wasteful number, since it uses less digits than its factorization.

21716126421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14001432.

The product of its digits is 8064, while the sum is 33.

The spelling of 21716126421 in words is "twenty-one billion, seven hundred sixteen million, one hundred twenty-six thousand, four hundred twenty-one".