2561366406620 has 24 divisors (see below), whose sum is σ = 6147279376224. Its totient is φ = 878182767936.

The previous prime is 2561366406593. The next prime is 2561366406623. The reversal of 2561366406620 is 266046631652.

It is a happy number.

It is a super-2 number, since 2×2561366406620² (a number of 26 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2561366406623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9147737027 + ... + 9147737306.

It is an arithmetic number, because the mean of its divisors is an integer number (256136640676).

Almost surely, 2^{2561366406620} is an apocalyptic number.

2561366406620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2561366406620 is an abundant number, since it is smaller than the sum of its proper divisors (3585912969604).

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

2561366406620 is a wasteful number, since it uses less digits than its factorization.

2561366406620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18295474349 (or 18295474347 counting only the distinct ones).

The product of its (nonzero) digits is 1866240, while the sum is 47.

The spelling of 2561366406620 in words is "two trillion, five hundred sixty-one billion, three hundred sixty-six million, four hundred six thousand, six hundred twenty".