261631503 has 24 divisors (see below), whose sum is σ = 435066528. Its totient is φ = 148407552.

The previous prime is 261631493. The next prime is 261631523. The reversal of 261631503 is 305136162.

261631503 is a `hidden beast` number, since 26 + 1 + 631 + 5 + 0 + 3 = 666.

It is not a de Polignac number, because 261631503 - 2⁵ = 261631471 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261631523) 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, 6526 + ... + 23787.

It is an arithmetic number, because the mean of its divisors is an integer number (18127772).

Almost surely, 2^261631503 is an apocalyptic number.

261631503 is a deficient number, since it is larger than the sum of its proper divisors (173435025).

261631503 is a wasteful number, since it uses less digits than its factorization.

261631503 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30463 (or 30460 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 27.

The square root of 261631503 is about 16175.0271406264. The cubic root of 261631503 is about 639.5826567839.

Adding to 261631503 its reverse (305136162), we get a palindrome (566767665).

The spelling of 261631503 in words is "two hundred sixty-one million, six hundred thirty-one thousand, five hundred three".