261993077897 has 12 divisors (see below), whose sum is σ = 277189983120. Its totient is φ = 246943354896.

The previous prime is 261993077861. The next prime is 261993077939. The reversal of 261993077897 is 798770399162.

It is not a de Polignac number, because 261993077897 - 2⁸ = 261993077641 is a prime.

It is not an unprimeable number, because it can be changed into a prime (261993077597) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 559718 + ... + 915024.

It is an arithmetic number, because the mean of its divisors is an integer number (23099165260).

Almost surely, 2^261993077897 is an apocalyptic number.

It is an amenable number.

261993077897 is a deficient number, since it is larger than the sum of its proper divisors (15196905223).

261993077897 is an equidigital number, since it uses as much as digits as its factorization.

261993077897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 355720 (or 355523 counting only the distinct ones).

The product of its (nonzero) digits is 72013536, while the sum is 68.

The spelling of 261993077897 in words is "two hundred sixty-one billion, nine hundred ninety-three million, seventy-seven thousand, eight hundred ninety-seven".