20420496487 has 4 divisors (see below), whose sum is σ = 21495259480. Its totient is φ = 19345733496.

The previous prime is 20420496469. The next prime is 20420496491. The reversal of 20420496487 is 78469402402.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78469402402 = 2 ⋅39234701201.

It is a cyclic number.

It is not a de Polignac number, because 20420496487 - 2²³ = 20412107879 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20420496787) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 537381468 + ... + 537381505.

It is an arithmetic number, because the mean of its divisors is an integer number (5373814870).

Almost surely, 2^20420496487 is an apocalyptic number.

20420496487 is a deficient number, since it is larger than the sum of its proper divisors (1074762993).

20420496487 is a wasteful number, since it uses less digits than its factorization.

20420496487 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1074762992.

The product of its (nonzero) digits is 774144, while the sum is 46.

Adding to 20420496487 its reverse (78469402402), we get a palindrome (98889898889).

The spelling of 20420496487 in words is "twenty billion, four hundred twenty million, four hundred ninety-six thousand, four hundred eighty-seven".