261764777772 has 36 divisors (see below), whose sum is σ = 661805249560. Its totient is φ = 87238829952.

The previous prime is 261764777767. The next prime is 261764777783. The reversal of 261764777772 is 277777467162.

It is a happy number.

261764777772 is a `hidden beast` number, since 2 + 617 + 6 + 4 + 7 + 7 + 7 + 7 + 7 + 2 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Smith number, since the sum of its digits (63) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 471997 + ... + 863892.

Almost surely, 2^261764777772 is an apocalyptic number.

It is an amenable number.

261764777772 is an abundant number, since it is smaller than the sum of its proper divisors (400040471788).

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

261764777772 is a wasteful number, since it uses less digits than its factorization.

261764777772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1341342 (or 1341337 counting only the distinct ones).

The product of its digits is 67765824, while the sum is 63.

The spelling of 261764777772 in words is "two hundred sixty-one billion, seven hundred sixty-four million, seven hundred seventy-seven thousand, seven hundred seventy-two".