261971607515 has 8 divisors (see below), whose sum is σ = 315750802320. Its totient is φ = 208654037152.

The previous prime is 261971607511. The next prime is 261971607559. The reversal of 261971607515 is 515706179162.

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 261971607515 - 2² = 261971607511 is a prime.

It is not an unprimeable number, because it can be changed into a prime (261971607511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 115404860 + ... + 115407129.

It is an arithmetic number, because the mean of its divisors is an integer number (39468850290).

Almost surely, 2^261971607515 is an apocalyptic number.

261971607515 is a deficient number, since it is larger than the sum of its proper divisors (53779194805).

261971607515 is a wasteful number, since it uses less digits than its factorization.

261971607515 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 230812221.

The product of its (nonzero) digits is 793800, while the sum is 50.

The spelling of 261971607515 in words is "two hundred sixty-one billion, nine hundred seventy-one million, six hundred seven thousand, five hundred fifteen".