20403575681 has 4 divisors (see below), whose sum is σ = 20407180500. Its totient is φ = 20399970864.

The previous prime is 20403575653. The next prime is 20403575683. The reversal of 20403575681 is 18657530402.

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

It can be written as a sum of positive squares in 2 ways, for example, as 10546263025 + 9857312656 = 102695^2 + 99284^2 .

It is a cyclic number.

It is not a de Polignac number, because 20403575681 - 2¹⁰ = 20403574657 is a prime.

It is a super-2 number, since 2×20403575681² (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 (20403575683) 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, 1793906 + ... + 1805243.

It is an arithmetic number, because the mean of its divisors is an integer number (5101795125).

Almost surely, 2^20403575681 is an apocalyptic number.

It is an amenable number.

20403575681 is a deficient number, since it is larger than the sum of its proper divisors (3604819).

20403575681 is an equidigital number, since it uses as much as digits as its factorization.

20403575681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3604818.

The product of its (nonzero) digits is 201600, while the sum is 41.

The spelling of 20403575681 in words is "twenty billion, four hundred three million, five hundred seventy-five thousand, six hundred eighty-one".