261645646657415 has 32 divisors (see below), whose sum is σ = 338680956430080. Its totient is φ = 193404647310336.

The previous prime is 261645646657399. The next prime is 261645646657441. The reversal of 261645646657415 is 514756646546162.

It is a cyclic number.

It is not a de Polignac number, because 261645646657415 - 2⁴ = 261645646657399 is a prime.

It is a super-2 number, since 2×261645646657415² (a number of 30 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 44098922 + ... + 49679031.

It is an arithmetic number, because the mean of its divisors is an integer number (10583779888440).

Almost surely, 2^{261645646657415} is an apocalyptic number.

261645646657415 is a deficient number, since it is larger than the sum of its proper divisors (77035309772665).

261645646657415 is a wasteful number, since it uses less digits than its factorization.

261645646657415 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 93778703.

The product of its digits is 870912000, while the sum is 68.

The spelling of 261645646657415 in words is "two hundred sixty-one trillion, six hundred forty-five billion, six hundred forty-six million, six hundred fifty-seven thousand, four hundred fifteen".