21115664473 has 8 divisors (see below), whose sum is σ = 21414486240. Its totient is φ = 20818211040.

The previous prime is 21115664461. The next prime is 21115664483. The reversal of 21115664473 is 37446651112.

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 21115664473 - 2¹⁷ = 21115533401 is a prime.

It is a super-2 number, since 2×21115664473² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21115664483) 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, 310983 + ... + 372748.

It is an arithmetic number, because the mean of its divisors is an integer number (2676810780).

Almost surely, 2^21115664473 is an apocalyptic number.

It is an amenable number.

21115664473 is a deficient number, since it is larger than the sum of its proper divisors (298821767).

21115664473 is an equidigital number, since it uses as much as digits as its factorization.

21115664473 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 684167.

The product of its digits is 120960, while the sum is 40.

The spelling of 21115664473 in words is "twenty-one billion, one hundred fifteen million, six hundred sixty-four thousand, four hundred seventy-three".