21018418708471 has 2 divisors, whose sum is σ = 21018418708472. Its totient is φ = 21018418708470.

The previous prime is 21018418708453. The next prime is 21018418708481. The reversal of 21018418708471 is 17480781481012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21018418708471 - 2¹⁷ = 21018418577399 is a prime.

It is a super-3 number, since 3×21018418708471³ (a number of 41 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21018418708481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10509209354235 + 10509209354236.

It is an arithmetic number, because the mean of its divisors is an integer number (10509209354236).

Almost surely, 2^{21018418708471} is an apocalyptic number.

21018418708471 is a deficient number, since it is larger than the sum of its proper divisors (1).

21018418708471 is an equidigital number, since it uses as much as digits as its factorization.

21018418708471 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 802816, while the sum is 52.

The spelling of 21018418708471 in words is "twenty-one trillion, eighteen billion, four hundred eighteen million, seven hundred eight thousand, four hundred seventy-one".