21465151221 has 8 divisors (see below), whose sum is σ = 28620878400. Its totient is φ = 14309762432.

The previous prime is 21465151187. The next prime is 21465151229. The reversal of 21465151221 is 12215156412.

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 21465151221 - 2²¹ = 21463054069 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21465151229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 207301 + ... + 293093.

It is an arithmetic number, because the mean of its divisors is an integer number (3577609800).

Almost surely, 2^21465151221 is an apocalyptic number.

It is an amenable number.

21465151221 is a deficient number, since it is larger than the sum of its proper divisors (7155727179).

21465151221 is an equidigital number, since it uses as much as digits as its factorization.

21465151221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 169195.

The product of its digits is 4800, while the sum is 30.

The spelling of 21465151221 in words is "twenty-one billion, four hundred sixty-five million, one hundred fifty-one thousand, two hundred twenty-one".