263665206261 has 12 divisors (see below), whose sum is σ = 400894465920. Its totient is φ = 166525393320.

The previous prime is 263665206197. The next prime is 263665206281. The reversal of 263665206261 is 162602566362.

263665206261 is a `hidden beast` number, since 2 + 6 + 3 + 6 + 6 + 520 + 62 + 61 = 666.

It is not a de Polignac number, because 263665206261 - 2⁶ = 263665206197 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (263665206281) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 770950725 + ... + 770951066.

It is an arithmetic number, because the mean of its divisors is an integer number (33407872160).

Almost surely, 2^263665206261 is an apocalyptic number.

It is an amenable number.

263665206261 is a deficient number, since it is larger than the sum of its proper divisors (137229259659).

263665206261 is a wasteful number, since it uses less digits than its factorization.

263665206261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1541901816 (or 1541901813 counting only the distinct ones).

The product of its (nonzero) digits is 933120, while the sum is 45.

The spelling of 263665206261 in words is "two hundred sixty-three billion, six hundred sixty-five million, two hundred six thousand, two hundred sixty-one".