21156215151065 has 8 divisors (see below), whose sum is σ = 25387482868800. Its totient is φ = 16924955662512.

The previous prime is 21156215151037. The next prime is 21156215151083. The reversal of 21156215151065 is 56015151265112.

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 21156215151065 - 2²⁰ = 21156214102489 is a prime.

It is an unprimeable number.

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, 9066386 + ... + 11158484.

It is an arithmetic number, because the mean of its divisors is an integer number (3173435358600).

Almost surely, 2^{21156215151065} is an apocalyptic number.

It is an amenable number.

21156215151065 is a deficient number, since it is larger than the sum of its proper divisors (4231267717735).

21156215151065 is a wasteful number, since it uses less digits than its factorization.

21156215151065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4114591.

The product of its (nonzero) digits is 90000, while the sum is 41.

The spelling of 21156215151065 in words is "twenty-one trillion, one hundred fifty-six billion, two hundred fifteen million, one hundred fifty-one thousand, sixty-five".