21166235447 has 8 divisors (see below), whose sum is σ = 24194401152. Its totient is φ = 18139174200.

The previous prime is 21166235401. The next prime is 21166235479. The reversal of 21166235447 is 74453266112.

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

It is not a de Polignac number, because 21166235447 - 2⁶ = 21166235383 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21166235347) 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, 234629 + ... + 312062.

It is an arithmetic number, because the mean of its divisors is an integer number (3024300144).

Almost surely, 2^21166235447 is an apocalyptic number.

21166235447 is a deficient number, since it is larger than the sum of its proper divisors (3028165705).

21166235447 is an equidigital number, since it uses as much as digits as its factorization.

21166235447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 552229.

The product of its digits is 241920, while the sum is 41.

The spelling of 21166235447 in words is "twenty-one billion, one hundred sixty-six million, two hundred thirty-five thousand, four hundred forty-seven".