261616971 has 16 divisors (see below), whose sum is σ = 434896128. Its totient is φ = 135904800.

The previous prime is 261616969. The next prime is 261616991. The reversal of 261616971 is 179616162.

It is not a de Polignac number, because 261616971 - 2¹ = 261616969 is a prime.

It is not an unprimeable number, because it can be changed into a prime (261616921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 566040 + ... + 566501.

It is an arithmetic number, because the mean of its divisors is an integer number (27181008).

Almost surely, 2^261616971 is an apocalyptic number.

261616971 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

261616971 is a deficient number, since it is larger than the sum of its proper divisors (173279157).

261616971 is a wasteful number, since it uses less digits than its factorization.

261616971 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1132562.

The product of its digits is 27216, while the sum is 39.

The square root of 261616971 is about 16174.5779233957. The cubic root of 261616971 is about 639.5708149540.

The spelling of 261616971 in words is "two hundred sixty-one million, six hundred sixteen thousand, nine hundred seventy-one".