20867117718721 has 4 divisors (see below), whose sum is σ = 20878270642944. Its totient is φ = 20855964794500.

The previous prime is 20867117718719. The next prime is 20867117718787. The reversal of 20867117718721 is 12781771176802.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20867117718721 - 2¹ = 20867117718719 is a prime.

It is a super-2 number, since 2×20867117718721² (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 (20867117718121) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5576459305 + ... + 5576463046.

It is an arithmetic number, because the mean of its divisors is an integer number (5219567660736).

Almost surely, 2^{20867117718721} is an apocalyptic number.

It is an amenable number.

20867117718721 is a deficient number, since it is larger than the sum of its proper divisors (11152924223).

20867117718721 is a wasteful number, since it uses less digits than its factorization.

20867117718721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11152924222.

The product of its (nonzero) digits is 3687936, while the sum is 58.

The spelling of 20867117718721 in words is "twenty trillion, eight hundred sixty-seven billion, one hundred seventeen million, seven hundred eighteen thousand, seven hundred twenty-one".