261606305620 has 48 divisors (see below), whose sum is σ = 609474196800. Its totient is φ = 93517195520.

The previous prime is 261606305603. The next prime is 261606305629. The reversal of 261606305620 is 26503606162.

It is a self number, because there is not a number n which added to its sum of digits gives 261606305620.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261606305629) 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 15 ways as a sum of consecutive naturals, for example, 10064305 + ... + 10090264.

It is an arithmetic number, because the mean of its divisors is an integer number (12697379100).

Almost surely, 2^261606305620 is an apocalyptic number.

261606305620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261606305620 is an abundant number, since it is smaller than the sum of its proper divisors (347867891180).

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

261606305620 is a wasteful number, since it uses less digits than its factorization.

261606305620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20154648 (or 20154646 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 37.

The spelling of 261606305620 in words is "two hundred sixty-one billion, six hundred six million, three hundred five thousand, six hundred twenty".