20656441781 has 8 divisors (see below), whose sum is σ = 21141584640. Its totient is φ = 20171515392.

The previous prime is 20656441777. The next prime is 20656441783. The reversal of 20656441781 is 18714465602.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20656441781 - 2² = 20656441777 is a prime.

It is a super-2 number, since 2×20656441781² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20656441783) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 147701 + ... + 251253.

It is an arithmetic number, because the mean of its divisors is an integer number (2642698080).

Almost surely, 2^20656441781 is an apocalyptic number.

It is an amenable number.

20656441781 is a deficient number, since it is larger than the sum of its proper divisors (485142859).

20656441781 is a wasteful number, since it uses less digits than its factorization.

20656441781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108235.

The product of its (nonzero) digits is 322560, while the sum is 44.

The spelling of 20656441781 in words is "twenty billion, six hundred fifty-six million, four hundred forty-one thousand, seven hundred eighty-one".