261554507776 has 117 divisors (see below), whose sum is σ = 535850461029. Its totient is φ = 127651430400.

The previous prime is 261554507771. The next prime is 261554507791. The reversal of 261554507776 is 677705455162.

The square root of 261554507776 is 511424.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 8505266176 + 253049241600 = 92224^2 + 503040^2 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261554507771) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1996599231 + ... + 1996599361.

Almost surely, 2^261554507776 is an apocalyptic number.

261554507776 is the 511424-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261554507776

261554507776 is an abundant number, since it is smaller than the sum of its proper divisors (274295953253).

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

261554507776 is an frugal number, since it uses more digits than its factorization.

261554507776 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 408 (or 194 counting only the distinct ones).

The product of its (nonzero) digits is 12348000, while the sum is 55.

The spelling of 261554507776 in words is "two hundred sixty-one billion, five hundred fifty-four million, five hundred seven thousand, seven hundred seventy-six".