20690171689 has 4 divisors (see below), whose sum is σ = 22571096400. Its totient is φ = 18809246980.

The previous prime is 20690171651. The next prime is 20690171729. The reversal of 20690171689 is 98617109602.

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 20690171689 - 2¹⁵ = 20690138921 is a prime.

It is a super-2 number, since 2×20690171689² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20690171609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 940462339 + ... + 940462360.

It is an arithmetic number, because the mean of its divisors is an integer number (5642774100).

Almost surely, 2^20690171689 is an apocalyptic number.

It is an amenable number.

20690171689 is a deficient number, since it is larger than the sum of its proper divisors (1880924711).

20690171689 is a wasteful number, since it uses less digits than its factorization.

20690171689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1880924710.

The product of its (nonzero) digits is 326592, while the sum is 49.

The spelling of 20690171689 in words is "twenty billion, six hundred ninety million, one hundred seventy-one thousand, six hundred eighty-nine".