21406041647 has 8 divisors (see below), whose sum is σ = 21508007760. Its totient is φ = 21304241920.

The previous prime is 21406041637. The next prime is 21406041697. The reversal of 21406041647 is 74614060412.

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

It is a cyclic number.

It is not a de Polignac number, because 21406041647 - 2⁶ = 21406041583 is a prime.

It is a super-3 number, since 3×21406041647³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21406041637) 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, 220223 + ... + 302175.

It is an arithmetic number, because the mean of its divisors is an integer number (2688500970).

Almost surely, 2^21406041647 is an apocalyptic number.

21406041647 is a deficient number, since it is larger than the sum of its proper divisors (101966113).

21406041647 is an equidigital number, since it uses as much as digits as its factorization.

21406041647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83193.

The product of its (nonzero) digits is 32256, while the sum is 35.

The spelling of 21406041647 in words is "twenty-one billion, four hundred six million, forty-one thousand, six hundred forty-seven".