20919061171 has 4 divisors (see below), whose sum is σ = 20920718344. Its totient is φ = 20917404000.

The previous prime is 20919061157. The next prime is 20919061193. The reversal of 20919061171 is 17116091902.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20919061171 - 2²⁵ = 20885506739 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20919061171.

It is not an unprimeable number, because it can be changed into a prime (20919061571) 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, 809505 + ... + 834946.

It is an arithmetic number, because the mean of its divisors is an integer number (5230179586).

Almost surely, 2^20919061171 is an apocalyptic number.

20919061171 is a deficient number, since it is larger than the sum of its proper divisors (1657173).

20919061171 is a wasteful number, since it uses less digits than its factorization.

20919061171 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1657172.

The product of its (nonzero) digits is 6804, while the sum is 37.

The spelling of 20919061171 in words is "twenty billion, nine hundred nineteen million, sixty-one thousand, one hundred seventy-one".