261477531 has 16 divisors (see below), whose sum is σ = 442713600. Its totient is φ = 149415624.

The previous prime is 261477499. The next prime is 261477533. The reversal of 261477531 is 135774162.

It is a happy number.

261477531 is a `hidden beast` number, since 2 + 614 + 7 + 7 + 5 + 31 = 666.

It is not a de Polignac number, because 261477531 - 2⁵ = 261477499 is a prime.

It is a super-2 number, since 2×261477531² = 136740998435711922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (261477533) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 691551 + ... + 691928.

It is an arithmetic number, because the mean of its divisors is an integer number (27669600).

Almost surely, 2^261477531 is an apocalyptic number.

261477531 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

261477531 is a deficient number, since it is larger than the sum of its proper divisors (181236069).

261477531 is a wasteful number, since it uses less digits than its factorization.

261477531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1383495 (or 1383489 counting only the distinct ones).

The product of its digits is 35280, while the sum is 36.

The square root of 261477531 is about 16170.2668809145. The cubic root of 261477531 is about 639.4571658493.

The spelling of 261477531 in words is "two hundred sixty-one million, four hundred seventy-seven thousand, five hundred thirty-one".