21375172117617 has 16 divisors (see below), whose sum is σ = 28725215188992. Its totient is φ = 14137626384000.

The previous prime is 21375172117577. The next prime is 21375172117627. The reversal of 21375172117617 is 71671127157312.

It is not a de Polignac number, because 21375172117617 - 2⁷ = 21375172117489 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21375172117617.

It is not an unprimeable number, because it can be changed into a prime (21375172117627) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19451367 + ... + 20520867.

It is an arithmetic number, because the mean of its divisors is an integer number (1795325949312).

Almost surely, 2^{21375172117617} is an apocalyptic number.

It is an amenable number.

21375172117617 is a deficient number, since it is larger than the sum of its proper divisors (7350043071375).

21375172117617 is a wasteful number, since it uses less digits than its factorization.

21375172117617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1122088.

The product of its digits is 864360, while the sum is 51.

The spelling of 21375172117617 in words is "twenty-one trillion, three hundred seventy-five billion, one hundred seventy-two million, one hundred seventeen thousand, six hundred seventeen".