20731605403 has 4 divisors (see below), whose sum is σ = 20745492768. Its totient is φ = 20717718040.

The previous prime is 20731605371. The next prime is 20731605409. The reversal of 20731605403 is 30450613702.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 30450613702 = 2 ⋅15225306851.

It is a cyclic number.

It is not a de Polignac number, because 20731605403 - 2⁵ = 20731605371 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20731605409) 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, 6941443 + ... + 6944428.

It is an arithmetic number, because the mean of its divisors is an integer number (5186373192).

Almost surely, 2^20731605403 is an apocalyptic number.

20731605403 is a deficient number, since it is larger than the sum of its proper divisors (13887365).

20731605403 is a wasteful number, since it uses less digits than its factorization.

20731605403 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13887364.

The product of its (nonzero) digits is 15120, while the sum is 31.

The spelling of 20731605403 in words is "twenty billion, seven hundred thirty-one million, six hundred five thousand, four hundred three".