261552403011501 has 64 divisors (see below), whose sum is σ = 452646314864640. Its totient is φ = 146167035693120.

The previous prime is 261552403011481. The next prime is 261552403011583. The reversal of 261552403011501 is 105110304255162.

261552403011501 is a `hidden beast` number, since 2 + 6 + 1 + 552 + 40 + 3 + 0 + 11 + 50 + 1 = 666.

It is not a de Polignac number, because 261552403011501 - 2⁹ = 261552403010989 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261552403011101) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 38863575 + ... + 45094148.

It is an arithmetic number, because the mean of its divisors is an integer number (7072598669760).

Almost surely, 2^{261552403011501} is an apocalyptic number.

261552403011501 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

261552403011501 is a deficient number, since it is larger than the sum of its proper divisors (191093911853139).

261552403011501 is a wasteful number, since it uses less digits than its factorization.

261552403011501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83958103 (or 83958097 counting only the distinct ones).

The product of its (nonzero) digits is 36000, while the sum is 36.

Adding to 261552403011501 its reverse (105110304255162), we get a palindrome (366662707266663).

The spelling of 261552403011501 in words is "two hundred sixty-one trillion, five hundred fifty-two billion, four hundred three million, eleven thousand, five hundred one".