261631783 has 16 divisors (see below), whose sum is σ = 311512320. Its totient is φ = 215064000.

The previous prime is 261631757. The next prime is 261631793. The reversal of 261631783 is 387136162.

It is a cyclic number.

It is not a de Polignac number, because 261631783 - 2¹⁷ = 261500711 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261631703) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9208 + ... + 24658.

It is an arithmetic number, because the mean of its divisors is an integer number (19469520).

Almost surely, 2^261631783 is an apocalyptic number.

261631783 is a deficient number, since it is larger than the sum of its proper divisors (49880537).

261631783 is a wasteful number, since it uses less digits than its factorization.

261631783 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15558.

The product of its digits is 36288, while the sum is 37.

The square root of 261631783 is about 16175.0357959418. The cubic root of 261631783 is about 639.5828849458.

The spelling of 261631783 in words is "two hundred sixty-one million, six hundred thirty-one thousand, seven hundred eighty-three".