2156454777780 has 72 divisors (see below), whose sum is σ = 6541700092200. Its totient is φ = 575014701312.

The previous prime is 2156454777779. The next prime is 2156454777797. The reversal of 2156454777780 is 877774546512.

It is a happy number.

2156454777780 is a `hidden beast` number, since 2 + 1 + 5 + 6 + 4 + 547 + 7 + 7 + 7 + 80 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 823164256656 + 1333290521124 = 907284^2 + 1154682^2 .

It is a super-2 number, since 2×2156454777780² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2232066 + ... + 3048774.

It is an arithmetic number, because the mean of its divisors is an integer number (90856945725).

Almost surely, 2^{2156454777780} is an apocalyptic number.

2156454777780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2156454777780 is an abundant number, since it is smaller than the sum of its proper divisors (4385245314420).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

2156454777780 is a wasteful number, since it uses less digits than its factorization.

2156454777780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 831393 (or 831388 counting only the distinct ones).

The product of its (nonzero) digits is 92198400, while the sum is 63.

The spelling of 2156454777780 in words is "two trillion, one hundred fifty-six billion, four hundred fifty-four million, seven hundred seventy-seven thousand, seven hundred eighty".