261780773 has 8 divisors (see below), whose sum is σ = 280295640. Its totient is φ = 243612160.

The previous prime is 261780731. The next prime is 261780781. The reversal of 261780773 is 377087162.

It can be written as a sum of positive squares in 4 ways, for example, as 36990724 + 224790049 = 6082^2 + 14993^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 261780773 - 2¹⁸ = 261518629 is a prime.

It is a super-2 number, since 2×261780773² = 137058346224955058, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 261780773.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261780793) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 84998 + ... + 88023.

It is an arithmetic number, because the mean of its divisors is an integer number (35036955).

Almost surely, 2^261780773 is an apocalyptic number.

It is an amenable number.

261780773 is a deficient number, since it is larger than the sum of its proper divisors (18514867).

261780773 is a wasteful number, since it uses less digits than its factorization.

261780773 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 173127.

The product of its (nonzero) digits is 98784, while the sum is 41.

The square root of 261780773 is about 16179.6406944036. The cubic root of 261780773 is about 639.7042684800.

The spelling of 261780773 in words is "two hundred sixty-one million, seven hundred eighty thousand, seven hundred seventy-three".