2778810015861 has 48 divisors (see below), whose sum is σ = 4394111641920. Its totient is φ = 1678214453760.

The previous prime is 2778810015853. The next prime is 2778810015881. The reversal of 2778810015861 is 1685100188772.

It is not a de Polignac number, because 2778810015861 - 2³ = 2778810015853 is a prime.

It is a super-2 number, since 2×2778810015861² (a number of 26 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 2778810015798 and 2778810015807.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2778810015881) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 152229411 + ... + 152247663.

It is an arithmetic number, because the mean of its divisors is an integer number (91543992540).

Almost surely, 2^{2778810015861} is an apocalyptic number.

It is an amenable number.

2778810015861 is a deficient number, since it is larger than the sum of its proper divisors (1615301626059).

2778810015861 is a wasteful number, since it uses less digits than its factorization.

2778810015861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23586 (or 23583 counting only the distinct ones).

The product of its (nonzero) digits is 1505280, while the sum is 54.

The spelling of 2778810015861 in words is "two trillion, seven hundred seventy-eight billion, eight hundred ten million, fifteen thousand, eight hundred sixty-one".