636140261 has 8 divisors (see below), whose sum is σ = 639655680. Its totient is φ = 632634912.

The previous prime is 636140189. The next prime is 636140287. The reversal of 636140261 is 162041636.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 636140261 - 2¹⁰ = 636139237 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (636145261) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 147806 + ... + 152048.

It is an arithmetic number, because the mean of its divisors is an integer number (79956960).

Almost surely, 2^636140261 is an apocalyptic number.

It is an amenable number.

636140261 is a deficient number, since it is larger than the sum of its proper divisors (3515419).

636140261 is a wasteful number, since it uses less digits than its factorization.

636140261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5035.

The product of its (nonzero) digits is 5184, while the sum is 29.

The square root of 636140261 is about 25221.8211277457. The cubic root of 636140261 is about 860.0379742561.

Adding to 636140261 its reverse (162041636), we get a palindrome (798181897).

The spelling of 636140261 in words is "six hundred thirty-six million, one hundred forty thousand, two hundred sixty-one".