261895216651 has 8 divisors (see below), whose sum is σ = 269781699600. Its totient is φ = 254080104960.

The previous prime is 261895216621. The next prime is 261895216657. The reversal of 261895216651 is 156612598162.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261895216651 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261895216657) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17835366 + ... + 17850043.

It is an arithmetic number, because the mean of its divisors is an integer number (33722712450).

Almost surely, 2^261895216651 is an apocalyptic number.

261895216651 is a deficient number, since it is larger than the sum of its proper divisors (7886482949).

261895216651 is a wasteful number, since it uses less digits than its factorization.

261895216651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35685629.

The product of its digits is 1555200, while the sum is 52.

The spelling of 261895216651 in words is "two hundred sixty-one billion, eight hundred ninety-five million, two hundred sixteen thousand, six hundred fifty-one".