21512155671017 has 8 divisors (see below), whose sum is σ = 23476196569152. Its totient is φ = 19549513170000.

The previous prime is 21512155671011. The next prime is 21512155671037. The reversal of 21512155671017 is 71017655121512.

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

It is not a de Polignac number, because 21512155671017 - 2⁴ = 21512155671001 is a prime.

It is a super-2 number, since 2×21512155671017² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21512155671011) 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, 349567109 + ... + 349628642.

It is an arithmetic number, because the mean of its divisors is an integer number (2934524571144).

Almost surely, 2^{21512155671017} is an apocalyptic number.

It is an amenable number.

21512155671017 is a deficient number, since it is larger than the sum of its proper divisors (1964040898135).

21512155671017 is a wasteful number, since it uses less digits than its factorization.

21512155671017 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 699198559.

The product of its (nonzero) digits is 147000, while the sum is 44.

The spelling of 21512155671017 in words is "twenty-one trillion, five hundred twelve billion, one hundred fifty-five million, six hundred seventy-one thousand, seventeen".