20456641891 has 8 divisors (see below), whose sum is σ = 23380792064. Its totient is φ = 17532934920.

The previous prime is 20456641889. The next prime is 20456641903. The reversal of 20456641891 is 19814665402.

It is a happy number.

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 20456641891 - 2¹ = 20456641889 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20456641291) 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, 5175 + ... + 202336.

It is an arithmetic number, because the mean of its divisors is an integer number (2922599008).

Almost surely, 2^20456641891 is an apocalyptic number.

20456641891 is a deficient number, since it is larger than the sum of its proper divisors (2924150173).

20456641891 is a wasteful number, since it uses less digits than its factorization.

20456641891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 221601.

The product of its (nonzero) digits is 414720, while the sum is 46.

The spelling of 20456641891 in words is "twenty billion, four hundred fifty-six million, six hundred forty-one thousand, eight hundred ninety-one".