20786815861 has 16 divisors (see below), whose sum is σ = 24162817536. Its totient is φ = 17513573616.

The previous prime is 20786815859. The next prime is 20786815891. The reversal of 20786815861 is 16851868702.

It is not a de Polignac number, because 20786815861 - 2¹ = 20786815859 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20786815799 and 20786815808.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20786815831) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 171570 + ... + 266476.

It is an arithmetic number, because the mean of its divisors is an integer number (1510176096).

Almost surely, 2^20786815861 is an apocalyptic number.

It is an amenable number.

20786815861 is a deficient number, since it is larger than the sum of its proper divisors (3376001675).

20786815861 is an equidigital number, since it uses as much as digits as its factorization.

20786815861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95448.

The product of its (nonzero) digits is 1290240, while the sum is 52.

It can be divided in two parts, 207868 and 15861, that added together give a square (223729 = 473²).

The spelling of 20786815861 in words is "twenty billion, seven hundred eighty-six million, eight hundred fifteen thousand, eight hundred sixty-one".