261163136421 has 24 divisors (see below), whose sum is σ = 411549053760. Its totient is φ = 158273280000.

The previous prime is 261163136411. The next prime is 261163136447. The reversal of 261163136421 is 124631361162.

261163136421 is a `hidden beast` number, since 2 + 6 + 1 + 1 + 6 + 3 + 1 + 3 + 642 + 1 = 666.

It is not a de Polignac number, because 261163136421 - 2¹⁰ = 261163135397 is a prime.

It is a super-3 number, since 3×261163136421³ (a number of 35 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261163136401) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2672421 + ... + 2768421.

It is an arithmetic number, because the mean of its divisors is an integer number (17147877240).

Almost surely, 2^261163136421 is an apocalyptic number.

It is an amenable number.

261163136421 is a deficient number, since it is larger than the sum of its proper divisors (150385917339).

261163136421 is a wasteful number, since it uses less digits than its factorization.

261163136421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123497 (or 123494 counting only the distinct ones).

The product of its digits is 31104, while the sum is 36.

Adding to 261163136421 its reverse (124631361162), we get a palindrome (385794497583).

The spelling of 261163136421 in words is "two hundred sixty-one billion, one hundred sixty-three million, one hundred thirty-six thousand, four hundred twenty-one".